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A couple magnetic starter/relay questions

I have a magnetic starter on my table saw. It consists of a on(momentary close)/off(momentary open) switch and a 4 pole relay. On of the poles fused closed so I used another pole. Since then it has worked, but has been flaky. I figure it is time to replace the relay. As long as I am doing that, I am changing from 120v to 240v. I bought an Omron 07J 4A B relay.

1) On the old 120v relay, a hot wire went to a pole and then to the Off switch. The other wire to the off switch is a neutral. Presumably (since this relay has a 240v coil) I run a hot to the switch instead of the neutral. But do I have to run it to the relay first, so that both hots run through the relay, or is just one adequate. It can't hurt to do both, but I can use the old wiring as is if I just do one. Are both necessary? (yes, of course I will run each hot to the motor through the relay)

2) There were no instructions with the relay. It has 10 contacts:

13,14,23,24,33/31,34/32,43/41,44/42,A1,A2. Looking at their website, I "think" that the coil is A1,A2 and all the others are NO poles. I "think" the weird double numbering is because they use the same mold to make relays that have 1 or 2 NC poles. Does this seem right?

3) The relay has screw terminals. Rather than fuss with trying to get wires under them, I will crimp connectors on to the wires and just stick the connectors under the screws. That is okay, isn't it?

Thanks.

Reply to
John
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With a 240 volt relay coil, the coil must be connected to both hots. All you need to do is change the plug so that it connects (properly) to a 240 receptacle. That will automatically put a hot where the neutral was.

Why not post the url so we can see the diagram you refer to?

Yup.

Don't forget to re-wire to the motor terminals for 240!

Reply to
ehsjr

Answer: NEC 2002 430.84 Need Not Open All Conductors. The controller shall not be required to open all conductors to the motor. Exception: Where the controller serves also as a disconnecting means, it shall open all ungrounded conductors to the motor as provided in 430.111.

Anwser: This is manufacturer specific.

Answer: You can install the wires under the screws or use terminals. Terminals are very expensive so many contractors skip the terminals to save on material and labor costs. As a matter of fact, I know one contractor that instructs electricians to not use terminals for these very reasons, and they build UL listed panels that do not use terminals.

Reply to
Gerald Newton
040526 1757 - John posted:

Magnetic STOP START Controller Overload ---?--- Coil Contacts

----O__|__ O---|---O O--|--------()()()()()---------|\|---|\|----- | | | | ------| |----- Controller Auxilliary Contact

Controller Contact Thermal Device L1-----------| |------------~~~~~~~~-----------MOTOR------------L2

Here is a standard circuit for a motor controller. In your case, L1, and L2 would be 220 volts, and so would the feed to the stop button and overload contacts.

Reply to
indago

So, I wasted my money buying a 4pole relay when a 2 pole would have done the job. Is that about it?!

Thanks.

on(momentary

Contacts

Reply to
John
040527 2215 - John posted:

Actually, no; you do need 3 controller contacts: two for the motor -- since it is a 220 volt motor, and one for the auxilliary contact. I have revised the diagram to indicate the extra contact for the motor.

Reply to
indago

While it is better to interrupt both hot leads to the motor, it is not required. See NEC 430.84 as G.Newton pointed out.

Reply to
ehsjr

Controller

Only one leg of the motor is required for controlling the motor if the controller is not used as a disconnect per code.

Reply to
Gerald Newton

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