Square D Contactor... need urgent help!

[bjp_ne_elec]

I'm still confused.
The coil is 480V, but you say you are only feeding it with 277V. Is the stop button connected to L1 and the overload relay contact to L2?

If your control circuit does not included a grounded conductor, you should not be using ground (or neutral) as a reference point when making voltage measurements.

I'm assuming Greg is measuring the voltage at the Stop/Start to ground. He'd have to have one lead to the L2 side to get the 480. As the Stop/Start is close you could easily get the other lead of the DVM to the L2 side - but to your comment, if you had remote Stop/Start and were troubleshooting, you'd have no other recourse than to check your voltage referenced to ground.

Greg - did you get this working yet? It was sounding like you hadn't tied in the control voltage to to the Stop/Start. We're over 100 posts!

 

[Smart $]

...you'd have no other recourse than to check your voltage referenced to ground.

You'd get 480 across the "start" terminals in the stopped state.

 

[bjp_ne_elec]

You'd get 480 across the "start" terminals in the stopped state.

I stand corrected - Smart$ - you are 100% correct. We have to hear from Gregg to see what points he was measuring.

 

[hillbilly1]

Measuring to ground can be helpful, but misleading, I can't count how many times I've got a call from a tech saying that everything is hot because he took readings phase to ground instead of phase to phase, usually a blown fuse in one phase with the load still connected.

 

[jim dungar]

Measuring to ground can be helpful...

Only if the ground is solidly referenced to the point you are measuring. If your system is ungrounded, you will be measuring capacitive coupling which, as you said, can be very misleading.

 

[hillbilly1]

Ungrounded systems tend to be rare, but are out there for specific reasons. The systems that I am referencing are the normal run of the mill delta's and wye's, but yes if it is an ungrounded system you would have that. Reading only to ground on a grounded system that has a load connected will give a false reading due to voltage traveling thru the load back on the "dead" phase making it appear to be functional, but going phase to phase will show it non-functional if the fuse is blown.

 

[jim dungar]

Ungrounded systems tend to be rare...

Yes that may be true, but ungrounded control circuits are not as uncommon. But my point was intended to be more about choosing a reference point that is not part of the circuit being examined. If the OP needs 480V to his coil and he measures 277V L-G, is his control circuit working? By only measuring L-G voltage, could you determine that both ends of the control circuit were actually connected to L1?

 

[quogueelectric]

I am late to this party wish I had seen it sooner he is definitely missing a phase on his control ckt. Reading one phase probably measuring to ground I susspect a fuse block with 2- 600v fuses somewhere with one fuse blown and the other fuse backfeeding the ckt. Control ckt should come from L1/L2 or possibly L3 follow the wires down from the line side of the contactor and see where they go. It is the oldest mistake in the book where a backfeed fools the electrician into thinking he has power there. The second reason this theory floats is that it would be very unusual to fry a coil on a starter unless a wrong and higher voltage was applied. Find the blown control fuse and replace it Be careful with the 480 good luck.

 

[quogueelectric]

The o/l contact is usually on the L2 side of the coils control ckt there might be a problem with the overloads but if you replaced the unit i suspect a control fuse more likely. What type of ols are in the starter Eutectic solder/bimetalic/electronic telemacanique through ct loops????

 

[quogueelectric]

Where did everybody go????

 

[emahler]

beginning to think Greg and his J-man are still standing there looking at the system and trying to will it to work...

 

[Greg Swartz]

It is finished!

It is finished!

Well, I got things working.

Just got home, it is dinner time, and I need to check the kids homework. I will post more later!

 

[Rockyd]

I will post more later!


An inquiring forum wants to know the whole story

 

[Greg Swartz]

The truth, the whole truth, and nothing but the truth

The truth, the whole truth, and nothing but the truth

The truth, the whole truth, and nothing but the truth... or something close to it anyway.

So, we got the new contactor last Wednesday and the J-man went over to install it. When he removed the contactor, he labelled all the wires, and where they went...

Well, I don't think he labelled all the wires correctly...

So, he installed the new contactor / OL...

Well, he pressed the start button, the vacuum turned on, but the system would not stay engaged. (So, the coil was not staying closed...)

Anyway, he called me, I asked a bunch of questions, he hung up, and about 1/2 hour later I called him, wondering why he had not called back...

Well, he says that he is really frustrated, that the system just blew up in his face, and that he is calling it a day (by this time, it's 4:00... Wednesday before Thanksgiving) I am headed to a job so that I can pass out checks to the guys on the commercial jobsite, and my service electrician has just blown up a 480V contactor / overload... I am trying to be grateful that no one got hurt...

However, this is the second time he has tried to fix the issue... and the second time he has blown it up... (the first being my original post)

About 6:00 PM, I stop by to see the job, and looking at things with a flashlight, I can't see anything wrong. I see flash marks on a couple of wires.
Apparently, he tried to bypass a Square D "quick connect" and I think he crossed 2 wires... (today I saw some burnt wires...)

So, I head home, and try to focus on Thanksgiving...

Question to self: What are you thankful for? Not a single thing, right now!

More to follow

 

[Greg Swartz]

So, I stop by the office on Friday to finish the week's time cards and look online for not just a contactor / OL, but the entire bucket... I was pissed, and I didn't really have the time to go figure this out... That's what I hired this J-man for...

So, after quite a while, I have not found anything, I call it a day, and Monday morning, I tell the J-man to come to the office...

I tell him to go to the carwash, pull the contactor, and the start stop station... bring it to the office, and write out a schematic...

Well, the whole idea was a foreign concept to him.

I started going over every wire with him... every location... even the "why" of each wire...

I show him (again) the drawing that Dave Pritchard sent me.

I am constantly having to leave him and take calls or work on stuff...
He tells me that he did not believe that the time was of any value to him, that we are still as lost as we were on Wednesday.

That upset me. I spent my time with him, and he tells me, that there was no value... I kept my temper under control.

I asked him what would benefit him to make sure that the circuit was installed correctly... he really did not have an answer, because he did not know what caused the thing to blow up.

More to follow...

 

[emahler]

shoot...i was pretty close....Greg was willing his j-man to get it right

 

[Greg Swartz]

To back up a bit: Monday morning, I called up everybody's favorite Cow: Sherman!

We went over the circuit by phone, and I walked over quite a bit of ground with him...

I had ordered a new unit... again... to be overnighted by Tuesday morning.

So, I get the new unit in today... the J-man says that he wants me to look at everything before he turns anything on. I agree.

I get to the job about 1/2 hour after he does, and he's putting the finishing touches on the unit.

I look everything over, double check all the wires, and there are 2 control wires that are not sitting well with me...

I am looking at them, and the J-man leans over and says to me "I am going to be leaving you."

I reply, "OK, when."

He says, "Friday"

I acknowledge him, and resume looking at the wiring... I question him on the 2 wires... he tells me that the wires were that way all along...

I turn the unit on and nothing blows up... I check voltages everywhere. I press the the "Start" button, and the contactor pulls in. I release, the contactor releases... Ok, we are at the same point as Friday night.

I call my favorite Cow again... we walk the circuit... I see where the problem is... it is the 2 wires I was curious about. I hang up with Sherman, and the J-man tells me he has to go and pick up his kids... I tell him, it is only 3:00...

So, he leaves... I fix the 2 wires, and add a jumper...

No sparks, no flash of light... it just... WORKS!

Yet more to follow

 

[ceb58]

Greg, how much more are you going to spend to fix this problem? The screw through the wire the first time could be written off to crap happens. But now how many days and dollars later do you still not have this thing working? Put your self in the customers shoes, guy comes to work on something, screws it up, comes back with more parts, blows them up. Your creditability is going down the tubes quick. Bite the bullet, turn off the cell phone, turn off the computer go fix the thing your self and be done with it. But not before you have the JW sweeping the shop, raking leaves, shoveling snow something he can do and not cost you a arm and a leg.

 

[Greg Swartz]

So, the system works...

Now to add the auxiliary Start / Stop switch...

I check the wiring, ohm out the wires, and hook them up...

Hook the start in parallel, and the stop in series... not a problem...

The contactor drops out again...

Start troubleshooting everything I did... I pull the new stop portion out of the circuit... everything works fine...

Pull the Stop / Start button apart, and the stop is not working right... it's just plain open... probably from when he fried the system putting a screw through a wire.

I call CED... they got one more on the shelf... I swap the part out...

Fly back to the car wash, put the new S / S in... and the switches work properly...

Hook up the load to the system, and after 5 seconds, the OL trips... I boost it up 3 times before it stops tripping...

So, had the guys at the car wash put the unit to the test... and it performs well.

So, the S / S works in all positions, and nothing trips...

 

[Greg Swartz]

shoot...i was pretty close....Greg was willing his j-man to get it right

Yeah, I was... I'm trying to run a business. I took my tools off this summer. If I constantly go back into the field, how am I going to build a business. If I am constantly there, how are the guys going to work without me...

That's my thought process anyway...

Greg, how much more are you going to spend to fix this problem? The screw through the wire the first time could be written off to crap happens. But now how many days and dollars later do you still not have this thing working? Put your self in the customers shoes, guy comes to work on something, screws it up, comes back with more parts, blows them up. Your creditability is going down the tubes quick. Bite the bullet, turn off the cell phone, turn off the computer go fix the thing your self and be done with it. But not before you have the JW sweeping the shop, raking leaves, shoveling snow something he can do and not cost you a arm and a leg.

Honestly... I know what you are saying... as I said above^^^
But, eventually, I did have to fix the problem... and I made the whole thing work.

The owner is quite happy, and, had he not had a backup, I would not have stopped until everything worked. The last time I had an issue (not even similar in nature...) I worked on it literally all night... and before I left... everything worked...

However, now the JW will not be working for me past the end of the week... his choice...