ptonsparky
Tom
- Occupation
- EC - retired
Hooking equipment up to temp power source we find a 10 hp compressor that has run for years @ 480v. Coil on contactor is 240v. Is there enough impedance on this type of coil that it doesn't matter? SQ D.
DP contactor coil.
- Thread starter ptonsparky
- Start date
- Status
If you're asking if a 240V coil work on 480V then the answer is don't even think about trying it.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
If there is no transformer, did you see a neutral conductor involved in the control wiring? 480/sqrt(3) = 277 volts just about 15% over the coil rating. If the location is very far from the DP, actual local voltage could be lower than the 480 volts at the source giving the coil a lease in life. A control wiring diagram can be helpful here.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
Just buy a 480V coil for the contactor and be done with it.
ptonsparky
Tom
- Occupation
- EC - retired
It was connected 480 and had worked for years. No transformer. No connection to ground for 277.
No in line resistor.
We replaced the existing with the proper coil. And changed the overload heaters to reflect the amperage @ 480 vs 240.
No in line resistor.
We replaced the existing with the proper coil. And changed the overload heaters to reflect the amperage @ 480 vs 240.
So what exactly is it that you're asking?
ptonsparky
Tom
- Occupation
- EC - retired
Why, how did it work for so long? Any thing I miswired takes only seconds for the smoke to escape.
K8MHZ
Senior Member
- Occupation
- Electrician
They just don't make stuff like they used to......
Or, it did have the proper size coil and wasn't marked correctly.
ptonsparky
Tom
- Occupation
- EC - retired
Those are as good as any answer I have.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Got a model number and mfr of that DP contactor? Furnas, who was very big in DP contactors, had a dual voltage coil option, 240 or 480 sepending on how you connected it.
ptonsparky
Tom
- Occupation
- EC - retired
SQ D 998DA1V09 COIL Catalog shows it as a 208-240v
CL 8911 SER A TYPE DPS043 CONTACTOR Catalog shows this as 10hp 230v, 20hp 460v.
CL 8911 SER A TYPE DPS043 CONTACTOR Catalog shows this as 10hp 230v, 20hp 460v.
Still don't think you have explained the problem or even if there is one.
What was the applied voltage coil previously and what was its voltage rating?
What is the applied voltage coil now and what is its voltage rating?
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
Me too, I'd sure as hell smoke it if I wired it up...?:huh:
Did you ever meter the voltage when the coil sucked in to see if it stayed a true 480?
ptonsparky
Tom
- Occupation
- EC - retired
ptonsparky
Tom
- Occupation
- EC - retired
No, it had been running in the past when the guys were there. This is a fire damage job and we were hooking it back up to temp power. Most basic starter setup. Motor, starter, pressure switch. No more than 20' of wire from 600 amp feeder to Motor. Not now and not before the fire. Maybe 3' to and from the pressure switch.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Can you think of a third way to write that?
C'mon, give the guy some slack. Maybe it's just me, i can live with that.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
It was a joke - I thought it was pretty clear what he was asking about in the first post. I'd be similarly surprised to find the coil still working too!
T
T.M.Haja Sahib
Guest
Measure the impedance of that odd coil applying 480V or 240V AC and compare it with that of the new installed 480V coil.This may reveal the secret,if there is any!
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