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View Full Version : Control wiring for motor starter... clarification help.



Arthur.Marks
09-23-2010, 10:17 PM
Here is the manufacturer supplied schematic:
http://i771.photobucket.com/albums/xx357/Arrak_Thumrs/Drill%20Press%20Rewire/control.jpg
My question is with the 230V control wiring. As shown: A1(M)A2......96(OL)95

What is "customer supplied jumper"? I assumed that meant just take a wire (I used 12ga) and connect the two...is that incorrect?

So I currently have it wired as follows; 230V control incoming power, of course, has two legs. Both legs go through an On/Off switch first. From there, one leg is connected to A1. The other leg is connected to 95. I have A2 and 96 connected directly as stated. Is my wiring correct?

HSS
09-23-2010, 10:28 PM
Yes, that will work but the only way to shut off the device you are controlling with the motor starter is to shut off the power going to it. The jumper shown as customer supplied is for a switch or thermostat or some other interupt to interupt the power to the motor starter coil which is labled "M". If you leave off the jumper, the coil will not pull in the contacts and the device will not come on. If you make the jumper a switch, the device will come on when you turn on the switch and will be protected by the overloads labled "OL". You are aware that this is a 3 phase motor starter, aren't you?

Patrick

MaxHeadRoom
09-23-2010, 10:39 PM
It would also be the point where you would wire in a N.O. start button in series with a N.C. stop button, the auxiliary contact, 13 &14 would be wired across the N.O. start as a retaining contact, these would be wired in, in place of the jumper.
A google of stop/start circuitry should show you many examples.
Here is one that shows a 24v coil, but the principle is the same.
http://support.automationdirect.com/docs/an-mc-004.pdf
Max.

HSS
09-23-2010, 11:03 PM
Too much sugar for a dime, Max. All you need in this circuit is an off/on switch, like a light switch. If the switch is on, the contacts stay closed. Turn off the switch and the contacts open. Just keeping it simple. Don't need the expense of the push button switches when a 79 cent light switch will do the same thing.

Arthur.Marks
09-23-2010, 11:07 PM
Okay. So I have the switch for the control in the wrong spot, then.

Yes, I am aware of the 3~. The incoming power to the machine is 3~. The motor is 3~. Two legs are used to power the 230V control. Here's the next question, then. The two incoming 230V power legs: One is connected to A1 the other is connected to 95. Then only one line goes from A2, is wired into the On/Off switch; and then one line from the switch to 96. Correct?

Also to clarify, I already have the switch. It is a simple On/Off affair.

HSS
09-23-2010, 11:13 PM
yes, one wire from A2 to the switch then a wire from the other terminal on the switch to 96. Are you picking up the 230 volts from the topside of the starter?

Arthur.Marks
09-23-2010, 11:32 PM
yes, one wire from A2 to the switch then a wire from the other terminal on the switch to 96. Are you picking up the 230 volts from the topside of the starter?

There is a fuse wired in each incoming line before the starter. So three fuses, three terminals. I connected an extra line at each exit of the two terminals to pick up the single phase control 230V.
http://i771.photobucket.com/albums/xx357/Arrak_Thumrs/Drill%20Press%20Rewire/230.jpg

MaxHeadRoom
09-24-2010, 09:29 AM
Too much sugar for a dime, Max. All you need in this circuit is an off/on switch, like a light switch. If the switch is on, the contacts stay closed. Turn off the switch and the contacts open. Just keeping it simple. Don't need the expense of the push button switches when a 79 cent light switch will do the same thing.

It depends if you want to conform to code and safety, lets say if the O/L tripped and you had left the switch on when the O/L was reset, the motor would restart right away, which may not be safe, depending on what the motor is for.
Also you may not want the motor to come on right away when the power is applied if the switch is left on.
Max.

HSS
09-24-2010, 09:29 AM
No, that won't work. You have to get your power from the topside, L1 & L2 for example.

HSS
09-24-2010, 09:48 AM
You are absolutely correct Max. If his equipment is being run by an employee, the push button switch is a must. However, if he is the only one using his equipment, he would probably be aware of what is going to happen when he turns the machine on. I guess it boils down to his call on which way he goes with the switch. But, you point is well taken. If he is uncertain about the safety of himself or others, he should get the push button on & off.
Patrick

Mark McGrath
09-24-2010, 10:26 AM
Terminals 95 and 96 are the NC contact on the thermal overload.The customer link usually goes from 96 to the contactor coil terminal which is A2.
If you wire the incoming 230 volts through an on/off switch the contactor will energise when you turn it on unless the overload has tripped thus opening 95-96.
It would be normal to operate it via stop and start buttons utilising the 13-14 NO auxillary contact.
Do a google for three wire control and it will all become clear.

Arthur.Marks
09-24-2010, 10:27 AM
Home shop. One operator (me). It is a drill press. As originally acquired, it did have an O/L dual push-button on/off switch that was damaged. This is what I chose for a replacement.

This is why I love this board. I had no idea that it was code to have the dual-button control when using an overload relay. In any case, it seems very unlikely that it would be a safety issue for me. To gain access to the reset, I would need to remove a front panel which the switch is on. I just couldn't see myself doing that without turning off the main disconnect box to the machine (final last words, right? :D ).

Arthur.Marks
09-24-2010, 12:24 PM
No, that won't work. You have to get your power from the topside, L1 & L2 for example.

Okay, I changed it; but...

I don't understand. As long as the fuse isn't blown, wouldn't the 230V control line be charged exactly the same whether it was originated at the fuse terminal (as previously illustrated) or at the incoming starter terminal (L1, L2) ???

Peter.
09-24-2010, 01:39 PM
I think the 'customer supplied jumper' is a provision to wire in a safety stop switch (the type you hit to stop but have to turn to reset).

MaxHeadRoom
09-24-2010, 02:15 PM
It would be normal to operate it via stop and start buttons utilising the 13-14 NO auxillary contact.
Do a google for three wire control and it will all become clear.

Or post #3 ;)
Max.

Mark McGrath
09-24-2010, 02:43 PM
Or post #3 ;)
Max.

Ah,sorry Max.I just skimmed the other posts.Great minds think alike.Plus it`s the correct way to do it.:D
Mark.

Mark McGrath
09-24-2010, 02:46 PM
I think the 'customer supplied jumper' is a provision to wire in a safety stop switch (the type you hit to stop but have to turn to reset).

No it`s not.
In Europe and elsewhere there are regulations as to how things are wired electrically.In Europe at least you would not put a stop button in between the overload contact and the contactor coil.

Mark.

HSS
09-25-2010, 08:52 AM
Okay, I changed it; but...

I don't understand. As long as the fuse isn't blown, wouldn't the 230V control line be charged exactly the same whether it was originated at the fuse terminal (as previously illustrated) or at the incoming starter terminal (L1, L2) ???

Arthur, what you have drawn and what the schematic shows are not the same. Upon another look at you drawing, it seems you are refering to T1, T2, and T3 as it comes from the fuse box to the starter box. If so, you can get the control power from there. But, if you look at the schematic first shown at the beginning of your post, it shows T1, T2, and T3 on the bottom side of the contacts and you would not be able to get 230 from there until the starter pulled in, which it wouldn't do without 230 volts to close the starter......
It's simpler to get your coil voltage from the same can the starter is in, especially if the switch is also located in the same area. Also, since the application is a drill press, I don't think a push button on/off switch is necessary. I can't imagine someone drilling to overload and not clearing the drill bit from the work before reset.

Patrick

Arthur.Marks
09-25-2010, 11:51 AM
Whoops. You're correct. What I drew was labelled incorrectly. The lines into the fuses should be labelled L1,L2,L3. In any case, it is now all wired up and works like a beauty. Thank you all for your help, it is truly appreciated!! :)