Electrical diagram question

This is how i wired the power circuit for a 208V reversing magnetic motor starter. It works but my question is should it have? My instructor was surprised it worked,he said draw the circuit and if it makes sense on a diagram now that it runs both ways properly he?ll credit me for the lab the way it was done. Does this circuit look like it should work or not?

Correct by me. it reverses the connections. Jim

Ok perfect thank you,I didn?t realize until later that I was supposed to remove the daisy chain connector on the top and reversing connector on the bottom first. This took a fair bit of trial and error. Here?s a picture of how we were supposed to wire it.

I'm thinking 5 and 8 have to be reversed.

What type/make of motor are you playing with, I don't recall ever seeing a single phase motor with that lead numbering sequence.

Just more evidence that electricity works on voodoo as much if not more than science 😂. Did he say why it shouldn?t have worked ?

They must be labeled differently between Canada and USA?

At first glance he said it should have shorted out.then he said he?d never seen it wired like that before and I?ll have to draw it out. I think it?s only a 10 minute change to remove the bars and replace with jumpers,I think I?ll do that first thing this morning so I?ll know how to do it the right way.

I wish I had paid a lot more attention in my electrical classes . I didn?t learn one thing my last semester in electrical or air conditioning class. Sounds like you got it figured out though

I (retired power distribution engineer) am asking the same type of question as Bob did below. I see 115/230 Phase 1 on the nameplate but read these responses and see wiring diagram, showing TWO L1 connections, and speaking of 208 (NOT 220/240) ?????

208 (as present in 208 Y 120 Volt Three Phase Four Wire Leg to Leg) IS NOT the same as 220/240 in Single Phase 3 Wire


Many non electricians and lay people DO NOT understand the difference in 240 Volt SINGLE Phase, as in typical home 120/240 Volt SINGLE Phase Three Wire service. That's 240 as was 220 or 230 in years past. Its possible to power a 220/240 Volt Single Phase Motor using L1 & L2 as its 240 Volts L1 to L2. Its ONLY 120 either L1 or L2 to Neutral.

VERSUS

208Y 120 Volt Three Phase Four Wire. That's 208 (NOT 220/240).

Of the three L1 L2 L3 legs in the 208Y 120 Volt Three Phase Four Wire Service, its possible to use say L1 to L2 (or L2 to L3) to power a 208 volt rated SINGLE phase motor.

SINGLE PHASE MOTORS REQUIRE TWO HOT PHASE CONDUCTORS (such as L1 & L2) WHILE THREE PHASE MOTORS REQUIRE THREE (L1 L2 L3) Sure, some devices can function on EITHER 208 or 220/240....

NOTE FYI In order to reverse a Three Phase motor (they are self starting) you simply switch/reverse any 2 of the 3 legs.

A Single Phase motor is NOT self starting and requires an out of phase separate start winding. Its the start
winding you switch so it starts spinning one way or the other


Nuff said lol and remember NO WARRANTY Im longgggggggg retired from power distribution design and rustyyyyyyyy but believe the above still remains true. Is easier to reverse a three phase self starting motor (swap any 2 legs) then a single phase (start winding)

John T

I was wondering about the connection diagram info on the motor.

No that?s completely true, it?s just to simulate we can reverse a single phase (240) volt motor if needed.we won?t be running anything with it just a wire start stop reverse stop tear it out situation. We just studied 3 phase,line voltage after a step down transformer can be 208 and in a delta the el=eph and in a wye eph=el/root 3 = 120v but a combination of the 2 phases are still only 208v because they?re 120 degrees out of phase with each other.

That's right one can reverse a single phase motor by changing the start winding configuration unlike a three phase (self starting motor) where alls required is reverse any two of the three phase lines. Line to Line in the 208 Y 120 Volt Three Phase Four Wire is obviously 208 and that's so L1 to L2 or L3 and vice versa. In years of practice I designed a ton of 240 or 480 Volt Three Phase DELTA systems but never any 208 Delta, instead the 208 Y 120. Although floating Delta was used for years, I preferred a grounded system. Sounds like you're getting a handle on all this, congratulations.

John T

Should you have the contacts marked NO and NC ?

Where I have it labeled 7 to T1,it?s actually supposed to be 1 to T1. I changed it first thing this morning. I pulled the 1-2-3 to 1-2-3 jumper off the top ,I took the 1-2-3 to 3-2-1 jumper off the bottom and replaced it with the 1-2-3 to 1-2-3. Then I wired the feeds L1 L2 L 1 and L1 L2 L2 and ran 1 from the motor to T1 8 to T2 and 4 to T3 tied 2,3&5 together and it started and ran in both forward and reverse.

Did you have to wire the interlocks to prevent both Fwd and Rev coils being energized at the same time?