wiring and relays question....

Contactor is just jargon for a bigger relay.
Not all coils are DC. In fact there is no reason to use a DC relay for this
job.
Does the machine have a "magnetic starter", which is more jargon for a
latching relay setup? If so, we can rig the gate switches to work with it
and all you'll need is wire. At 3 HP, I think it must have the mag.

Rather than microswitches, you'd use cheap pushbuttons...two at each gate,
to work the same as the ones in the mag.

The green button on the mag is normally open. When you push it, you power
the coil, which closes the relay and makes a pair of contacts that then
power the coil and hold the relay in. The red button is normally closed.
It's in series with the coil, so when you push it you break the coil circuit
and drop the relay.

SO, all your greens are normally open and connected in parallel with the big
one in the mag. All your reds are in series with the big one in the mag.
When you push any green, the DC starts. Red stops.

You can mount the buttons in surface mounted plug boxes using solid plates
drilled for the buttons. The wire can be 20 ga, since there is very little
current in the coil. HD should have some control wire rated for 120V.

If this isn't clear, drop me a note.

Wilson

"jduprie" <[email protected]> wrote in message
news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> Hi folks...
>
> Finally scored the Big Dust Collector (Oneida 3 hp), and am in the process
> of getting it hooked up. I was planning (OK, Hoping) to put microswitches
at
> the blast gates so I can turn the unit on/off by opening and closing the
> gates. Everything went fine in the planning phase, then when I actually
> started getting ready to put stuff together, I realized I had no idea how
to
> build the rely....
>
> Here's the stats:
> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
wants).
> I was hoping to use some simple low voltage DC for the switching - pretty
> much whatever low cost transformer I can find at Rat Shack, and switches
to
> go with it.
> I'm assuming that I just wire the whole thing up so that I've got the
> 220 feed going into the relay, the plug from the DC goes into the relay,
and
> the low voltage on/off controls the relay (DC current = on, no current =
> off). SO here's the big question: how do I figure out what size/type of
> relay I need? I've dug through all of my old (really old) electronic
> textbooks, and found lots of theory, but nothing of real practical value.
I
> dug through all of my industrial catalogues, and discovered that there are
> way more types of relays than I ever imagined. I searched the web, and got
> buried (no surprise there...).... So, having pretty much exhausted what my
> little brain could come up with, I figured I'd query the collective brain
> out there......
>
> Thanks to everyone.....
>
> __James J.B.N. DuPrie
>
>

I agree that if there is a magnetic switch it would be easier to use
that as a base but see no reason to put 2 buttons everywhere. the
microswitchs can be used with the mag switch directly, there is no need
to use the 'holding contacts" to keep it running. Check inside the
switch box or in the user manual for a schematic.

If you want scan, the schematic in and email to me, I can then let you
know how to reconfigure. Basic instruction would be to remove on wire
from the holding contacts (tape it up) run all the microswitches in
parallel with the start button.

I have a similar set up, 2HP Woodtek DC (manual switch) on a contactor
with a bell transformer and wooden microswitches(I built my own).

BRuce
[email protected] (remove the XXX)

Wilson Lamb wrote:
> Contactor is just jargon for a bigger relay.
> Not all coils are DC. In fact there is no reason to use a DC relay for this
> job.
> Does the machine have a "magnetic starter", which is more jargon for a
> latching relay setup? If so, we can rig the gate switches to work with it
> and all you'll need is wire. At 3 HP, I think it must have the mag.
>
> Rather than microswitches, you'd use cheap pushbuttons...two at each gate,
> to work the same as the ones in the mag.
>
> The green button on the mag is normally open. When you push it, you power
> the coil, which closes the relay and makes a pair of contacts that then
> power the coil and hold the relay in. The red button is normally closed.
> It's in series with the coil, so when you push it you break the coil circuit
> and drop the relay.
>
> SO, all your greens are normally open and connected in parallel with the big
> one in the mag. All your reds are in series with the big one in the mag.
> When you push any green, the DC starts. Red stops.
>
> You can mount the buttons in surface mounted plug boxes using solid plates
> drilled for the buttons. The wire can be 20 ga, since there is very little
> current in the coil. HD should have some control wire rated for 120V.
>
> If this isn't clear, drop me a note.
>
> Wilson
>
> "jduprie" <[email protected]> wrote in message
> news:ZeXbb.553283$Ho3.96729@sccrnsc03...
>
>>Hi folks...
>>
>>Finally scored the Big Dust Collector (Oneida 3 hp), and am in the process
>>of getting it hooked up. I was planning (OK, Hoping) to put microswitches
>
> at
>
>>the blast gates so I can turn the unit on/off by opening and closing the
>>gates. Everything went fine in the planning phase, then when I actually
>>started getting ready to put stuff together, I realized I had no idea how
>
> to
>
>>build the rely....
>>
>>Here's the stats:
>> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
>
> wants).
>
>>I was hoping to use some simple low voltage DC for the switching - pretty
>>much whatever low cost transformer I can find at Rat Shack, and switches
>
> to
>
>>go with it.
>> I'm assuming that I just wire the whole thing up so that I've got the
>>220 feed going into the relay, the plug from the DC goes into the relay,
>
> and
>
>>the low voltage on/off controls the relay (DC current = on, no current =
>>off). SO here's the big question: how do I figure out what size/type of
>>relay I need? I've dug through all of my old (really old) electronic
>>textbooks, and found lots of theory, but nothing of real practical value.
>
> I
>
>>dug through all of my industrial catalogues, and discovered that there are
>>way more types of relays than I ever imagined. I searched the web, and got
>>buried (no surprise there...).... So, having pretty much exhausted what my
>>little brain could come up with, I figured I'd query the collective brain
>>out there......
>>
>>Thanks to everyone.....
>>
>>__James J.B.N. DuPrie
>>
>>
>
>
>
>

there is no reason to "latch on" if it happens due to mechanical
failure then the stop button will not help. the part that holds it on
(when the start button is pushed)is the "holding or maintaining" contact
and that was taken out of the circuit. if a microswitch fails on then
it would be the same as the start button failing on. basic control
theory taken in high school.

A microswitch is just that, a very small switch, nothing magical happens
in a microswitch that doesn't happen in a regular switch. just 2 (or
more) contacts activated by a lever or other mechanism.

My switch are wooden forks with screw heads for the contacts, a wedge on
the gate forces the contacts open when the gate is closed. the failure
mode is to not com on when I open the gate but now that they are
"adjusted" that doesn't happen. simple, cheap and take about 10 minutes
to make a new on when I add a new gate. Bell wire all the switches in
parallel and any one closes and the DC comes on.

BRuce

Wilson Lamb wrote:
> How do you stop it if it latches on.
> Interesting that you'd build switches. "Microswitch" is a very specific
> type of switch with very small throw distance required. Expensive, unless
> you have scrounged some.
> Wilson
> <BRuce> wrote in message news:1064330249.617147@sj-nntpcache-5...
>
>>I agree that if there is a magnetic switch it would be easier to use
>>that as a base but see no reason to put 2 buttons everywhere. the
>>microswitchs can be used with the mag switch directly, there is no need
>>to use the 'holding contacts" to keep it running. Check inside the
>>switch box or in the user manual for a schematic.
>>
>>If you want scan, the schematic in and email to me, I can then let you
>>know how to reconfigure. Basic instruction would be to remove on wire
>>from the holding contacts (tape it up) run all the microswitches in
>>parallel with the start button.
>>
>>I have a similar set up, 2HP Woodtek DC (manual switch) on a contactor
>>with a bell transformer and wooden microswitches(I built my own).
>>
>>BRuce
>>[email protected] (remove the XXX)
>>
>>Wilson Lamb wrote:
>>
>>>Contactor is just jargon for a bigger relay.
>>>Not all coils are DC. In fact there is no reason to use a DC relay for
>
> this
>
>>>job.
>>>Does the machine have a "magnetic starter", which is more jargon for a
>>>latching relay setup? If so, we can rig the gate switches to work with
>
> it
>
>>>and all you'll need is wire. At 3 HP, I think it must have the mag.
>>>
>>>Rather than microswitches, you'd use cheap pushbuttons...two at each
>
> gate,
>
>>>to work the same as the ones in the mag.
>>>
>>>The green button on the mag is normally open. When you push it, you
>
> power
>
>>>the coil, which closes the relay and makes a pair of contacts that then
>>>power the coil and hold the relay in. The red button is normally
>
> closed.
>
>>>It's in series with the coil, so when you push it you break the coil
>
> circuit
>
>>>and drop the relay.
>>>
>>>SO, all your greens are normally open and connected in parallel with the
>
> big
>
>>>one in the mag. All your reds are in series with the big one in the
>
> mag.
>
>>>When you push any green, the DC starts. Red stops.
>>>
>>>You can mount the buttons in surface mounted plug boxes using solid
>
> plates
>
>>>drilled for the buttons. The wire can be 20 ga, since there is very
>
> little
>
>>>current in the coil. HD should have some control wire rated for 120V.
>>>
>>>If this isn't clear, drop me a note.
>>>
>>>Wilson
>>>
>>>"jduprie" <[email protected]> wrote in message
>>>news:ZeXbb.553283$Ho3.96729@sccrnsc03...
>>>
>>>
>>>>Hi folks...
>>>>
>>>>Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
>
> process
>
>>>>of getting it hooked up. I was planning (OK, Hoping) to put
>
> microswitches
>
>>>at
>>>
>>>
>>>>the blast gates so I can turn the unit on/off by opening and closing the
>>>>gates. Everything went fine in the planning phase, then when I actually
>>>>started getting ready to put stuff together, I realized I had no idea
>
> how
>
>>>to
>>>
>>>
>>>>build the rely....
>>>>
>>>>Here's the stats:
>>>> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
>>>
>>>wants).
>>>
>>>
>>>>I was hoping to use some simple low voltage DC for the switching -
>
> pretty
>
>>>>much whatever low cost transformer I can find at Rat Shack, and switches
>>>
>>>to
>>>
>>>
>>>>go with it.
>>>> I'm assuming that I just wire the whole thing up so that I've got
>
> the
>
>>>>220 feed going into the relay, the plug from the DC goes into the relay,
>>>
>>>and
>>>
>>>
>>>>the low voltage on/off controls the relay (DC current = on, no current =
>>>>off). SO here's the big question: how do I figure out what size/type of
>>>>relay I need? I've dug through all of my old (really old) electronic
>>>>textbooks, and found lots of theory, but nothing of real practical
>
> value.
>
>>>I
>>>
>>>
>>>>dug through all of my industrial catalogues, and discovered that there
>
> are
>
>>>>way more types of relays than I ever imagined. I searched the web, and
>
> got
>
>>>>buried (no surprise there...).... So, having pretty much exhausted what
>
> my
>
>>>>little brain could come up with, I figured I'd query the collective
>
> brain
>
>>>>out there......
>>>>
>>>>Thanks to everyone.....
>>>>
>>>>__James J.B.N. DuPrie
>>>>
>>>>
>>>
>>>
>>>
>>>
>
>

--
---

BRuce

You may want to look into a small contactor rather than a simple relay. The start up current and the
resulting sparks can burn out simple relays. The contactors lugs are amp rated.
"jduprie" <[email protected]> wrote in message news:ZeXbb.553283$Ho3.96729@sccrnsc03...
: Hi folks...
:
: Finally scored the Big Dust Collector (Oneida 3 hp), and am in the process
: of getting it hooked up. I was planning (OK, Hoping) to put microswitches at
: the blast gates so I can turn the unit on/off by opening and closing the
: gates. Everything went fine in the planning phase, then when I actually
: started getting ready to put stuff together, I realized I had no idea how to
: build the rely....
:
: Here's the stats:
: # HP motor, 220V, 20 Amp (at least that's the circuit breaker it wants).
: I was hoping to use some simple low voltage DC for the switching - pretty
: much whatever low cost transformer I can find at Rat Shack, and switches to
: go with it.
: I'm assuming that I just wire the whole thing up so that I've got the
: 220 feed going into the relay, the plug from the DC goes into the relay, and
: the low voltage on/off controls the relay (DC current = on, no current =
: off). SO here's the big question: how do I figure out what size/type of
: relay I need? I've dug through all of my old (really old) electronic
: textbooks, and found lots of theory, but nothing of real practical value. I
: dug through all of my industrial catalogues, and discovered that there are
: way more types of relays than I ever imagined. I searched the web, and got
: buried (no surprise there...).... So, having pretty much exhausted what my
: little brain could come up with, I figured I'd query the collective brain
: out there......
:
: Thanks to everyone.....
:
: __James J.B.N. DuPrie
:
:

Robert Bonomi wrote:
>
>[good stuff snipped]
>
> 'Poles' is simply how many separate wires you can switch at one time.
> For switching 120V loads, you only need a single pole (there's only one
> 'hot' wire), for 240V single-phase, you need a 'double pole' unit (two
> 'hot' wires),

Just a slight change in emphasis: for switching 120V loads, you must use
only a single pole (don't every switch the neutral). Same for 240:
double pole only.

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)

Robert Bonomi wrote:
>
> In article <[email protected]>,
> Pete Becker <[email protected]> wrote:
> >Robert Bonomi wrote:
> >>
> >>[good stuff snipped]
> >>
> >> 'Poles' is simply how many separate wires you can switch at one time.
> >> For switching 120V loads, you only need a single pole (there's only one
> >> 'hot' wire), for 240V single-phase, you need a 'double pole' unit (two
> >> 'hot' wires),
> >
> >Just a slight change in emphasis: for switching 120V loads, you must use
> >only a single pole (don't every switch the neutral). Same for 240:
> >double pole only.
> >
>
> Clarification: A relay with 'more poles than required' is *entirely* suitable
> for a task, all else being equal. No harm done by letting a set of contacts
> go 'unused'.

That's why I said "USE only a single pole." Okay, that's not really why
I said it -- I was thinking 'use a single pole relay'. But it does fit.
<g>

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)

jduprie wrote:
>
> OK.. I';ve been back to grainger and MSC catalogues, and the make a lot more
> sense now.... Still a question though:
>
> is there such a thing as a 20 amp, 220 volt, dual pole relay/contactor that
> uses low voltage DC for the coil? If I've got to run a 120 line to each
> switch, it kind of defeats the purpose... I was hoping to run low voltage
> wire to each balst gate, use a micro/mini switch (ciruit closes when blast
> gate is opened) to control the DC coil current.....
>

If you find a low voltage, low power relay, use it to control the big
one.

--

Pete Becker
Dinkumware, Ltd. (http://www.dinkumware.com)

Wilson Lamb wrote:
>
"Microswitch" is a very specific
> type of switch with very small throw distance required. Expensive, unless
> you have scrounged some.
> Wilson
>

NO! Microswitch Is a company that makes thousands of types of
switches.
...lew... (who at one time bought $12,000.00 worth of one kind) :-)

In article <ZeXbb.553283$Ho3.96729@sccrnsc03>, [email protected]
says...
--

I just finished mine and used a contactor from Grainger with 24vac coil
and microswitches, works great and made no mods on the DC.

On a relay there's two ratings. The first is how much current/volts it can
pass (ie 120 volts AC @ 10 amps) and the second is how much DC it takes to
switch the relay. I think the biggest relay that radio shack has is a 10 or
15 amp one. You'll have to find a 20 amp relay on the net.

"jduprie" <[email protected]> wrote in message
news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> Hi folks...
>
> Finally scored the Big Dust Collector (Oneida 3 hp), and am in the process
> of getting it hooked up. I was planning (OK, Hoping) to put microswitches
at
> the blast gates so I can turn the unit on/off by opening and closing the
> gates. Everything went fine in the planning phase, then when I actually
> started getting ready to put stuff together, I realized I had no idea how
to
> build the rely....
>
> Here's the stats:
> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
wants).
> I was hoping to use some simple low voltage DC for the switching - pretty
> much whatever low cost transformer I can find at Rat Shack, and switches
to
> go with it.
> I'm assuming that I just wire the whole thing up so that I've got the
> 220 feed going into the relay, the plug from the DC goes into the relay,
and
> the low voltage on/off controls the relay (DC current = on, no current =
> off). SO here's the big question: how do I figure out what size/type of
> relay I need? I've dug through all of my old (really old) electronic
> textbooks, and found lots of theory, but nothing of real practical value.
I
> dug through all of my industrial catalogues, and discovered that there are
> way more types of relays than I ever imagined. I searched the web, and got
> buried (no surprise there...).... So, having pretty much exhausted what my
> little brain could come up with, I figured I'd query the collective brain
> out there......
>
> Thanks to everyone.....
>
> __James J.B.N. DuPrie
>
>

In article <ZeXbb.553283$Ho3.96729@sccrnsc03>,
jduprie <[email protected]> wrote:
>Hi folks...
>
>Finally scored the Big Dust Collector (Oneida 3 hp), and am in the process
>of getting it hooked up. I was planning (OK, Hoping) to put microswitches at
>the blast gates so I can turn the unit on/off by opening and closing the
>gates. Everything went fine in the planning phase, then when I actually
>started getting ready to put stuff together, I realized I had no idea how to
>build the rely....
>
>Here's the stats:
> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it wants).
>I was hoping to use some simple low voltage DC for the switching - pretty
>much whatever low cost transformer I can find at Rat Shack, and switches to
>go with it.
> I'm assuming that I just wire the whole thing up so that I've got the
>220 feed going into the relay, the plug from the DC goes into the relay, and
>the low voltage on/off controls the relay (DC current = on, no current =
>off). SO here's the big question: how do I figure out what size/type of
>relay I need? I've dug through all of my old (really old) electronic
>textbooks, and found lots of theory, but nothing of real practical value. I
>dug through all of my industrial catalogues, and discovered that there are
>way more types of relays than I ever imagined. I searched the web, and got
>buried (no surprise there...).... So, having pretty much exhausted what my
>little brain could come up with, I figured I'd query the collective brain
>out there......

There are three 'significant' components in the description of a relay
(and several more 'minor' ones -- that are important only if you're trying
to match an _existing_ use).

1) the power requirements for the 'coil' -- what it takes to make the
relay pull in. This determines/is-determined-by the power on the
'control' circuit. Some are designed to run on AC, some on DC, and
voltages are 'anything you might want' -- from a few volts all the
way through 440V (or higher, if you get into the 'serious' industrial
catalogues <grin>). Then there's the matter of how much _current_ it
takes to energize the coil sufficiently for the relay to 'pull in'.
typical 'low voltage' (i.e. 48V or less), moderate-power-handling relays
need from a few tens of milliamps, to a few hundred milliamps. Devices
designed for switching high power levels will draw significantly more
power (have to move heavier contacts, and over larger distances, _faster_,
all of which requires more power. the 'larger distances, faster' is to
minimize the amount of 'arcing' that goes on.) For low-voltage relays,
sometimes the current is not expressly given, instead the resistance
(in 'ohms') of the coil is specified. OHM's law, describing the relation
of current, voltage, and resistance, in a circuit lets one use these
interchangably.

2) the power rating for the contacts. There'll be both a voltage, and a
current rating. As long as they're both higher than what you're
actually switching, everything is fine.

3) the 'configuration' of the contacts. Here you get to deal with
'poles' and 'throws'.

'Poles' is simply how many separate wires you can switch at one time.
For switching 120V loads, you only need a single pole (there's only one
'hot' wire), for 240V single-phase, you need a 'double pole' unit (two
'hot' wires), and for 3-phase, you need a 'triple pole' unit. to
accomplish a 'latching' action -- i.e., one push-button for 'on', and a
separate one for 'off', you'll need one _more_ pole than listed above.

'Throws' is the number of positions in which there is "a path" through
the device. Without getting into 'exotic' devices, there are just the
'single throw', and 'double throw' types to consider. Single-throw
makes contact in _one_ position only. Either 'normally closed', where
energizing the relay *opens* the circuit, or 'normally open', where
energizing the relay _closes_ the circuit. "double throw" devices have
_both_ kinds of contacts. When the relay is not energized, there is
continuity from the 'common' contact(s) to the 'normally closed' one(s).
when the relay _is_ energized, there is continuity between the 'common'
contact(s), and the 'normally open' one(s).

Just to complictate things, the 'double throw' types come in two
varieties -- 'make before break', and 'break before make'. This
describes what happens _as_ the relay changes state. In the first
variety, there is a 'momentary' period when _both_ sets of contacts
(the normally open _and_ normally closed ones) are connected to the
common contact. In the second type, there is a momentary period when
_neither_ set of contacts is connected to the common.


Assuming you're going to use a switch that is 'on' whenever a blast-gate is
open, you'll need a "double-pole, single-throw (normally open), 240V 20A
contacts" relay, with a coil voltage to match whatever cheapie transformer
you can scrounge. The commonest relays will have 6 or 12 volt coils. You
can _usually_ use an AC-rated coil with DC power, although it is a GOOD IDEA
to match the specifications. Trying to use a DC-rated coil with AC power will
'almost always' *not* work right -- the typical situation is that the relay
pulls in/out 120 times every second. Quite a buzz, lots of arcing, and *lousy*
power on the 'out' side of the relay. And the 'lifetime' of the device is
virtually non-existant.

In article <[email protected]>,
Pete Becker <[email protected]> wrote:
>Robert Bonomi wrote:
>>
>>[good stuff snipped]
>>
>> 'Poles' is simply how many separate wires you can switch at one time.
>> For switching 120V loads, you only need a single pole (there's only one
>> 'hot' wire), for 240V single-phase, you need a 'double pole' unit (two
>> 'hot' wires),
>
>Just a slight change in emphasis: for switching 120V loads, you must use
>only a single pole (don't every switch the neutral). Same for 240:
>double pole only.
>

Clarification: A relay with 'more poles than required' is *entirely* suitable
for a task, all else being equal. No harm done by letting a set of contacts
go 'unused'. Pete is correct about the need for care in wiring -- DO NOT EVER
switch the neutral.

The best advice, concerning electrical work:
"If you don't *know* what you're doing, _DON'T_DO_IT_! Get a pro, instead."

The work is -not- 'difficult', but 'one little mistake' can have _catastrophic_
results -- somebody gets killed, the house burns down, etc. It isn't worth the
risk.

If you _are_ considering "doing something" anyway, be sure to check local
_legal_ requirements, *and* potential effect on any insurance coverage.

I've known places where using an extension cord -- *any* extension cord,
including 'outlet strips' -- was illegal, by city ordinance. And homeowners
insurers who had a fixed policy, in the event of fires attributable to a
'defective' piece of equipment (household appliance, or whatever), of going
after the manufacturer to recover their payout.

In article <wp4cb.557483$YN5.376235@sccrnsc01>,
jduprie <[email protected]> wrote:
>OK.. I';ve been back to grainger and MSC catalogues, and the make a lot more
>sense now.... Still a question though:
>
>is there such a thing as a 20 amp, 220 volt, dual pole relay/contactor that
>uses low voltage DC for the coil? If I've got to run a 120 line to each
>switch, it kind of defeats the purpose... I was hoping to run low voltage
>wire to each balst gate, use a micro/mini switch (ciruit closes when blast
>gate is opened) to control the DC coil current.....
>
>Lots ogf relays/contactors from about $15 to about $500, but they all seem
>to want 120VAC (or more) for the coil...

Try <http://www.surplussales.com> select 'relays' from the main menu page,
then 'contactors' from that menu.

About 1/4 way down, there's a 24vac coil
240VAC double-pole single throw 'air conditioning' contactor, for $17.

half way down (in the 'medium contacteor' section, is a 25A 240v double-pole,
24VDC coil unit for $13

see also the "HVAC" list, from the main relays page.

I'd consider the 'Honeywell relay center' on the HVAC page as the power-
supply. rip out the relays that are in it, and substutite the $17 one above.
Voila! it's even in a code-compliant enclosure. :)

Or, you can probably get a "open frame' 24V transformer from Radio Shack
for under $10. Would still have to do up an enclosure, etc. -- might save
$10 when you're done. <grin>





>"jduprie" <[email protected]> wrote in message
>news:kJ3cb.563453$uu5.92821@sccrnsc04...
>> Wow.. Great info, but no magnetic starter (that I know of). I'm pretty
>sure
>> that buying it was option, and I didn't get it because I figured I'd be
>> doing the blast gate switch thing.....
>>
>> thanks
>> --JD
>>
>> "Wilson Lamb" <[email protected]> wrote in message
>> news:[email protected]...
>> > Contactor is just jargon for a bigger relay.
>> > Not all coils are DC. In fact there is no reason to use a DC relay for
>> this
>> > job.
>> > Does the machine have a "magnetic starter", which is more jargon for a
>> > latching relay setup? If so, we can rig the gate switches to work with
>it
>> > and all you'll need is wire. At 3 HP, I think it must have the mag.
>> >
>> > Rather than microswitches, you'd use cheap pushbuttons...two at each
>gate,
>> > to work the same as the ones in the mag.
>> >
>> > The green button on the mag is normally open. When you push it, you
>power
>> > the coil, which closes the relay and makes a pair of contacts that then
>> > power the coil and hold the relay in. The red button is normally
>closed.
>> > It's in series with the coil, so when you push it you break the coil
>> circuit
>> > and drop the relay.
>> >
>> > SO, all your greens are normally open and connected in parallel with the
>> big
>> > one in the mag. All your reds are in series with the big one in the
>mag.
>> > When you push any green, the DC starts. Red stops.
>> >
>> > You can mount the buttons in surface mounted plug boxes using solid
>plates
>> > drilled for the buttons. The wire can be 20 ga, since there is very
>> little
>> > current in the coil. HD should have some control wire rated for 120V.
>> >
>> > If this isn't clear, drop me a note.
>> >
>> > Wilson
>> >
>> > "jduprie" <[email protected]> wrote in message
>> > news:ZeXbb.553283$Ho3.96729@sccrnsc03...
>> > > Hi folks...
>> > >
>> > > Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
>> process
>> > > of getting it hooked up. I was planning (OK, Hoping) to put
>> microswitches
>> > at
>> > > the blast gates so I can turn the unit on/off by opening and closing
>the
>> > > gates. Everything went fine in the planning phase, then when I
>actually
>> > > started getting ready to put stuff together, I realized I had no idea
>> how
>> > to
>> > > build the rely....
>> > >
>> > > Here's the stats:
>> > > # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
>> > wants).
>> > > I was hoping to use some simple low voltage DC for the switching -
>> pretty
>> > > much whatever low cost transformer I can find at Rat Shack, and
>switches
>> > to
>> > > go with it.
>> > > I'm assuming that I just wire the whole thing up so that I've got
>> the
>> > > 220 feed going into the relay, the plug from the DC goes into the
>relay,
>> > and
>> > > the low voltage on/off controls the relay (DC current = on, no current
>=
>> > > off). SO here's the big question: how do I figure out what size/type
>of
>> > > relay I need? I've dug through all of my old (really old) electronic
>> > > textbooks, and found lots of theory, but nothing of real practical
>> value.
>> > I
>> > > dug through all of my industrial catalogues, and discovered that there
>> are
>> > > way more types of relays than I ever imagined. I searched the web, and
>> got
>> > > buried (no surprise there...).... So, having pretty much exhausted
>what
>> my
>> > > little brain could come up with, I figured I'd query the collective
>> brain
>> > > out there......
>> > >
>> > > Thanks to everyone.....
>> > >
>> > > __James J.B.N. DuPrie
>> > >
>> > >
>> >
>> >
>> >
>>
>>
>
>

Thanks! this is exactly what I was looking for.

--JD



"Robert Bonomi" <[email protected]> wrote in message
news:[email protected]...
> In article <wp4cb.557483$YN5.376235@sccrnsc01>,
> jduprie <[email protected]> wrote:
> >OK.. I';ve been back to grainger and MSC catalogues, and the make a lot
more
> >sense now.... Still a question though:
> >
> >is there such a thing as a 20 amp, 220 volt, dual pole relay/contactor
that
> >uses low voltage DC for the coil? If I've got to run a 120 line to each
> >switch, it kind of defeats the purpose... I was hoping to run low voltage
> >wire to each balst gate, use a micro/mini switch (ciruit closes when
blast
> >gate is opened) to control the DC coil current.....
> >
> >Lots ogf relays/contactors from about $15 to about $500, but they all
seem
> >to want 120VAC (or more) for the coil...
>
> Try <http://www.surplussales.com> select 'relays' from the main menu
page,
> then 'contactors' from that menu.
>
> About 1/4 way down, there's a 24vac coil
> 240VAC double-pole single throw 'air conditioning' contactor, for $17.
>
> half way down (in the 'medium contacteor' section, is a 25A 240v
double-pole,
> 24VDC coil unit for $13
>
> see also the "HVAC" list, from the main relays page.
>
> I'd consider the 'Honeywell relay center' on the HVAC page as the power-
> supply. rip out the relays that are in it, and substutite the $17 one
above.
> Voila! it's even in a code-compliant enclosure. :)
>
> Or, you can probably get a "open frame' 24V transformer from Radio Shack
> for under $10. Would still have to do up an enclosure, etc. -- might save
> $10 when you're done. <grin>
>
>
>
>
>
> >"jduprie" <[email protected]> wrote in message
> >news:kJ3cb.563453$uu5.92821@sccrnsc04...
> >> Wow.. Great info, but no magnetic starter (that I know of). I'm pretty
> >sure
> >> that buying it was option, and I didn't get it because I figured I'd be
> >> doing the blast gate switch thing.....
> >>
> >> thanks
> >> --JD
> >>
> >> "Wilson Lamb" <[email protected]> wrote in message
> >> news:[email protected]...
> >> > Contactor is just jargon for a bigger relay.
> >> > Not all coils are DC. In fact there is no reason to use a DC relay
for
> >> this
> >> > job.
> >> > Does the machine have a "magnetic starter", which is more jargon for
a
> >> > latching relay setup? If so, we can rig the gate switches to work
with
> >it
> >> > and all you'll need is wire. At 3 HP, I think it must have the mag.
> >> >
> >> > Rather than microswitches, you'd use cheap pushbuttons...two at each
> >gate,
> >> > to work the same as the ones in the mag.
> >> >
> >> > The green button on the mag is normally open. When you push it, you
> >power
> >> > the coil, which closes the relay and makes a pair of contacts that
then
> >> > power the coil and hold the relay in. The red button is normally
> >closed.
> >> > It's in series with the coil, so when you push it you break the coil
> >> circuit
> >> > and drop the relay.
> >> >
> >> > SO, all your greens are normally open and connected in parallel with
the
> >> big
> >> > one in the mag. All your reds are in series with the big one in the
> >mag.
> >> > When you push any green, the DC starts. Red stops.
> >> >
> >> > You can mount the buttons in surface mounted plug boxes using solid
> >plates
> >> > drilled for the buttons. The wire can be 20 ga, since there is very
> >> little
> >> > current in the coil. HD should have some control wire rated for
120V.
> >> >
> >> > If this isn't clear, drop me a note.
> >> >
> >> > Wilson
> >> >
> >> > "jduprie" <[email protected]> wrote in message
> >> > news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> >> > > Hi folks...
> >> > >
> >> > > Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
> >> process
> >> > > of getting it hooked up. I was planning (OK, Hoping) to put
> >> microswitches
> >> > at
> >> > > the blast gates so I can turn the unit on/off by opening and
closing
> >the
> >> > > gates. Everything went fine in the planning phase, then when I
> >actually
> >> > > started getting ready to put stuff together, I realized I had no
idea
> >> how
> >> > to
> >> > > build the rely....
> >> > >
> >> > > Here's the stats:
> >> > > # HP motor, 220V, 20 Amp (at least that's the circuit breaker
it
> >> > wants).
> >> > > I was hoping to use some simple low voltage DC for the switching -
> >> pretty
> >> > > much whatever low cost transformer I can find at Rat Shack, and
> >switches
> >> > to
> >> > > go with it.
> >> > > I'm assuming that I just wire the whole thing up so that I've
got
> >> the
> >> > > 220 feed going into the relay, the plug from the DC goes into the
> >relay,
> >> > and
> >> > > the low voltage on/off controls the relay (DC current = on, no
current
> >=
> >> > > off). SO here's the big question: how do I figure out what
size/type
> >of
> >> > > relay I need? I've dug through all of my old (really old)
electronic
> >> > > textbooks, and found lots of theory, but nothing of real practical
> >> value.
> >> > I
> >> > > dug through all of my industrial catalogues, and discovered that
there
> >> are
> >> > > way more types of relays than I ever imagined. I searched the web,
and
> >> got
> >> > > buried (no surprise there...).... So, having pretty much exhausted
> >what
> >> my
> >> > > little brain could come up with, I figured I'd query the collective
> >> brain
> >> > > out there......
> >> > >
> >> > > Thanks to everyone.....
> >> > >
> >> > > __James J.B.N. DuPrie
> >> > >
> >> > >
> >> >
> >> >
> >> >
> >>
> >>
> >
> >
>
>

Wow.. Great info, but no magnetic starter (that I know of). I'm pretty sure
that buying it was option, and I didn't get it because I figured I'd be
doing the blast gate switch thing.....

thanks
--JD

"Wilson Lamb" <[email protected]> wrote in message
news:[email protected]...
> Contactor is just jargon for a bigger relay.
> Not all coils are DC. In fact there is no reason to use a DC relay for
this
> job.
> Does the machine have a "magnetic starter", which is more jargon for a
> latching relay setup? If so, we can rig the gate switches to work with it
> and all you'll need is wire. At 3 HP, I think it must have the mag.
>
> Rather than microswitches, you'd use cheap pushbuttons...two at each gate,
> to work the same as the ones in the mag.
>
> The green button on the mag is normally open. When you push it, you power
> the coil, which closes the relay and makes a pair of contacts that then
> power the coil and hold the relay in. The red button is normally closed.
> It's in series with the coil, so when you push it you break the coil
circuit
> and drop the relay.
>
> SO, all your greens are normally open and connected in parallel with the
big
> one in the mag. All your reds are in series with the big one in the mag.
> When you push any green, the DC starts. Red stops.
>
> You can mount the buttons in surface mounted plug boxes using solid plates
> drilled for the buttons. The wire can be 20 ga, since there is very
little
> current in the coil. HD should have some control wire rated for 120V.
>
> If this isn't clear, drop me a note.
>
> Wilson
>
> "jduprie" <[email protected]> wrote in message
> news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> > Hi folks...
> >
> > Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
process
> > of getting it hooked up. I was planning (OK, Hoping) to put
microswitches
> at
> > the blast gates so I can turn the unit on/off by opening and closing the
> > gates. Everything went fine in the planning phase, then when I actually
> > started getting ready to put stuff together, I realized I had no idea
how
> to
> > build the rely....
> >
> > Here's the stats:
> > # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
> wants).
> > I was hoping to use some simple low voltage DC for the switching -
pretty
> > much whatever low cost transformer I can find at Rat Shack, and switches
> to
> > go with it.
> > I'm assuming that I just wire the whole thing up so that I've got
the
> > 220 feed going into the relay, the plug from the DC goes into the relay,
> and
> > the low voltage on/off controls the relay (DC current = on, no current =
> > off). SO here's the big question: how do I figure out what size/type of
> > relay I need? I've dug through all of my old (really old) electronic
> > textbooks, and found lots of theory, but nothing of real practical
value.
> I
> > dug through all of my industrial catalogues, and discovered that there
are
> > way more types of relays than I ever imagined. I searched the web, and
got
> > buried (no surprise there...).... So, having pretty much exhausted what
my
> > little brain could come up with, I figured I'd query the collective
brain
> > out there......
> >
> > Thanks to everyone.....
> >
> > __James J.B.N. DuPrie
> >
> >
>
>
>

How do you stop it if it latches on.
Interesting that you'd build switches. "Microswitch" is a very specific
type of switch with very small throw distance required. Expensive, unless
you have scrounged some.
Wilson
<BRuce> wrote in message news:1064330249.617147@sj-nntpcache-5...
> I agree that if there is a magnetic switch it would be easier to use
> that as a base but see no reason to put 2 buttons everywhere. the
> microswitchs can be used with the mag switch directly, there is no need
> to use the 'holding contacts" to keep it running. Check inside the
> switch box or in the user manual for a schematic.
>
> If you want scan, the schematic in and email to me, I can then let you
> know how to reconfigure. Basic instruction would be to remove on wire
> from the holding contacts (tape it up) run all the microswitches in
> parallel with the start button.
>
> I have a similar set up, 2HP Woodtek DC (manual switch) on a contactor
> with a bell transformer and wooden microswitches(I built my own).
>
> BRuce
> [email protected] (remove the XXX)
>
> Wilson Lamb wrote:
> > Contactor is just jargon for a bigger relay.
> > Not all coils are DC. In fact there is no reason to use a DC relay for
this
> > job.
> > Does the machine have a "magnetic starter", which is more jargon for a
> > latching relay setup? If so, we can rig the gate switches to work with
it
> > and all you'll need is wire. At 3 HP, I think it must have the mag.
> >
> > Rather than microswitches, you'd use cheap pushbuttons...two at each
gate,
> > to work the same as the ones in the mag.
> >
> > The green button on the mag is normally open. When you push it, you
power
> > the coil, which closes the relay and makes a pair of contacts that then
> > power the coil and hold the relay in. The red button is normally
closed.
> > It's in series with the coil, so when you push it you break the coil
circuit
> > and drop the relay.
> >
> > SO, all your greens are normally open and connected in parallel with the
big
> > one in the mag. All your reds are in series with the big one in the
mag.
> > When you push any green, the DC starts. Red stops.
> >
> > You can mount the buttons in surface mounted plug boxes using solid
plates
> > drilled for the buttons. The wire can be 20 ga, since there is very
little
> > current in the coil. HD should have some control wire rated for 120V.
> >
> > If this isn't clear, drop me a note.
> >
> > Wilson
> >
> > "jduprie" <[email protected]> wrote in message
> > news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> >
> >>Hi folks...
> >>
> >>Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
process
> >>of getting it hooked up. I was planning (OK, Hoping) to put
microswitches
> >
> > at
> >
> >>the blast gates so I can turn the unit on/off by opening and closing the
> >>gates. Everything went fine in the planning phase, then when I actually
> >>started getting ready to put stuff together, I realized I had no idea
how
> >
> > to
> >
> >>build the rely....
> >>
> >>Here's the stats:
> >> # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
> >
> > wants).
> >
> >>I was hoping to use some simple low voltage DC for the switching -
pretty
> >>much whatever low cost transformer I can find at Rat Shack, and switches
> >
> > to
> >
> >>go with it.
> >> I'm assuming that I just wire the whole thing up so that I've got
the
> >>220 feed going into the relay, the plug from the DC goes into the relay,
> >
> > and
> >
> >>the low voltage on/off controls the relay (DC current = on, no current =
> >>off). SO here's the big question: how do I figure out what size/type of
> >>relay I need? I've dug through all of my old (really old) electronic
> >>textbooks, and found lots of theory, but nothing of real practical
value.
> >
> > I
> >
> >>dug through all of my industrial catalogues, and discovered that there
are
> >>way more types of relays than I ever imagined. I searched the web, and
got
> >>buried (no surprise there...).... So, having pretty much exhausted what
my
> >>little brain could come up with, I figured I'd query the collective
brain
> >>out there......
> >>
> >>Thanks to everyone.....
> >>
> >>__James J.B.N. DuPrie
> >>
> >>
> >
> >
> >
> >
>

good idea... i had thought of it, but would prefer to use a single (simpler
cheaper) relay, I'm just not finding the ones I want....

thanks

--JD
"Pete Becker" <[email protected]> wrote in message
news:[email protected]...
> jduprie wrote:
> >
> > OK.. I';ve been back to grainger and MSC catalogues, and the make a lot
more
> > sense now.... Still a question though:
> >
> > is there such a thing as a 20 amp, 220 volt, dual pole relay/contactor
that
> > uses low voltage DC for the coil? If I've got to run a 120 line to each
> > switch, it kind of defeats the purpose... I was hoping to run low
voltage
> > wire to each balst gate, use a micro/mini switch (ciruit closes when
blast
> > gate is opened) to control the DC coil current.....
> >
>
> If you find a low voltage, low power relay, use it to control the big
> one.
>
> --
>
> Pete Becker
> Dinkumware, Ltd. (http://www.dinkumware.com)

OK.. I';ve been back to grainger and MSC catalogues, and the make a lot more
sense now.... Still a question though:

is there such a thing as a 20 amp, 220 volt, dual pole relay/contactor that
uses low voltage DC for the coil? If I've got to run a 120 line to each
switch, it kind of defeats the purpose... I was hoping to run low voltage
wire to each balst gate, use a micro/mini switch (ciruit closes when blast
gate is opened) to control the DC coil current.....

Lots ogf relays/contactors from about $15 to about $500, but they all seem
to want 120VAC (or more) for the coil...

thanks
--JD

"jduprie" <[email protected]> wrote in message
news:kJ3cb.563453$uu5.92821@sccrnsc04...
> Wow.. Great info, but no magnetic starter (that I know of). I'm pretty
sure
> that buying it was option, and I didn't get it because I figured I'd be
> doing the blast gate switch thing.....
>
> thanks
> --JD
>
> "Wilson Lamb" <[email protected]> wrote in message
> news:[email protected]...
> > Contactor is just jargon for a bigger relay.
> > Not all coils are DC. In fact there is no reason to use a DC relay for
> this
> > job.
> > Does the machine have a "magnetic starter", which is more jargon for a
> > latching relay setup? If so, we can rig the gate switches to work with
it
> > and all you'll need is wire. At 3 HP, I think it must have the mag.
> >
> > Rather than microswitches, you'd use cheap pushbuttons...two at each
gate,
> > to work the same as the ones in the mag.
> >
> > The green button on the mag is normally open. When you push it, you
power
> > the coil, which closes the relay and makes a pair of contacts that then
> > power the coil and hold the relay in. The red button is normally
closed.
> > It's in series with the coil, so when you push it you break the coil
> circuit
> > and drop the relay.
> >
> > SO, all your greens are normally open and connected in parallel with the
> big
> > one in the mag. All your reds are in series with the big one in the
mag.
> > When you push any green, the DC starts. Red stops.
> >
> > You can mount the buttons in surface mounted plug boxes using solid
plates
> > drilled for the buttons. The wire can be 20 ga, since there is very
> little
> > current in the coil. HD should have some control wire rated for 120V.
> >
> > If this isn't clear, drop me a note.
> >
> > Wilson
> >
> > "jduprie" <[email protected]> wrote in message
> > news:ZeXbb.553283$Ho3.96729@sccrnsc03...
> > > Hi folks...
> > >
> > > Finally scored the Big Dust Collector (Oneida 3 hp), and am in the
> process
> > > of getting it hooked up. I was planning (OK, Hoping) to put
> microswitches
> > at
> > > the blast gates so I can turn the unit on/off by opening and closing
the
> > > gates. Everything went fine in the planning phase, then when I
actually
> > > started getting ready to put stuff together, I realized I had no idea
> how
> > to
> > > build the rely....
> > >
> > > Here's the stats:
> > > # HP motor, 220V, 20 Amp (at least that's the circuit breaker it
> > wants).
> > > I was hoping to use some simple low voltage DC for the switching -
> pretty
> > > much whatever low cost transformer I can find at Rat Shack, and
switches
> > to
> > > go with it.
> > > I'm assuming that I just wire the whole thing up so that I've got
> the
> > > 220 feed going into the relay, the plug from the DC goes into the
relay,
> > and
> > > the low voltage on/off controls the relay (DC current = on, no current
=
> > > off). SO here's the big question: how do I figure out what size/type
of
> > > relay I need? I've dug through all of my old (really old) electronic
> > > textbooks, and found lots of theory, but nothing of real practical
> value.
> > I
> > > dug through all of my industrial catalogues, and discovered that there
> are
> > > way more types of relays than I ever imagined. I searched the web, and
> got
> > > buried (no surprise there...).... So, having pretty much exhausted
what
> my
> > > little brain could come up with, I figured I'd query the collective
> brain
> > > out there......
> > >
> > > Thanks to everyone.....
> > >
> > > __James J.B.N. DuPrie
> > >
> > >
> >
> >
> >
>
>