Connecting grinder to 220V line?

L1: first 220V line L2: second 220V line N: neutral -- voltage L1-N or L2-N is 120V G: ground

I would never go to the expense of running 4 wires when you only need 3. Nor do I believe that San Francisco code actually requires it, but there are amazing things in California laws. Your motor will use L1, L2 and G, of course.

GWE

Although it might be a good idea to run the N for future consideration. It can be left unused in the box.

Harold

I'm assuming this is a single phase motor with a centrifugal starter switch and possibly a start capacitor.

The motor should have a nameplate or label on it showing how those 6 wires get connected when used on 220V and 115V, make sure you follow the correct one for 230 volts.

If there's no diagram, but the leads are labeled, the following general instructions, which I cribbed from a newsgroup a while ago may help, but may also confuse:

First identify the leads coming out of the motor. They should have numbers on the leads like T1, T2, etc. A single phase dual voltage reversible motor should have: T1, T2, T3, T4, T5, and T8. They are: T1, T2, T3, T4 = Run winding leads, T5, T8 = Start winding leads. For 115V operation, the leads should be wired: T1 + T3 = L1 (Line input) T2 + T4 = L2 (Line input) T5 and T8 are wired to L1 and L2 and to reverse the motor, you reverse T5 and T8 with respect to L1 and L2 For 230V operation, the leads should be wired: T1 = L1, T4 = L2, T2 = T3 = T5 (just wire nut these three together.) T8 = L1 or L2 (depending on the motor rotation you require.)

L1 and L2 are of course the two "hot" leads in the conduit, and you should install a double pole switch rated for the horsepower of the motor you're using.

The neutral lead in the conduit won't connect to anything if it's only the motor that's being powered, just cap it off. If the circuit is also going to power a 115V load on the machine, like a work lamp, then the neutral will be required for the "return lead" of the work lamp and the "line side" of the work lamp switch will connect to either L1 or L2, take your pick.

The ground lead in the conduit will connect to the frame of the motor.

Since you are calling in an electrician anyway, why not have him eyeball the motor connections "just in case".

YMMV,

Jeff

I suspect - the instrument (machine) runs on 220v and the lamps on it at 120 and the G line to the frame for safety. The N is used as shown below - Leg (n) to N = 120v.

I think this is done (spec) to protect people like us - so we have 220 and 120 at the plug or at the drop point. Remember - the specs drive Electricians who bid on jobs and builders who cheap out when possible.

Martin

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Grant Erw>

I would ALWAYS put in the full 4 wires especially when you are talking about NM or UF cable. The cost is minimal, the labor and access is usually a bummer. If you are pulling it though conduit, I might let it ride for a while.

Jeff,

thanks. Now the picture is much clearer for me.

Alex

Jeff Wisnia wrote:

Because the grinder uses 110 volts for the light, the code WILL require 4 wires. Running the light from either L1 or L2 to ground will work - but it will NOT meet code - in California or in Canada.