Compressor not starting - not sure about relay and caps

[fredser]

Hi guys

Im new here and I hope someone would be so kind as to give me some advice.

Was given a Embraco T6222E compressor (which they say was working fine before) to replace a faulty compressor on one of my coldrooms. Problem is I didnt get the electrical box with it that holds the relay and caps. Was told by the local agents that any 1HP box will run this compressor. So I used a box that holds a 90-110mfd Starting Cap, 10mfd Running Cap and a 3ARR3A4AG3 relay.

When I tried to start it the compressor then hums and after 2 or 3 seconds the overload kicks out. Now on Embraco's website they say it must use a 88-108 start cap and 15mfd run cap and a 3ARR3B6V3 relay. Can this be the problem? Checked compressor for shorted windings (to earth and to eachother) but it seems fine.Amps measure about 30amps for that 2 seconds before it kicks out.

Any ideas please :confused:

[goshen]

Hi guys

Im new here and I hope someone would be so kind as to give me some advice.

Was given a Embraco T6222E compressor (which they say was working fine before) to replace a faulty compressor on one of my coldrooms. Problem is I didnt get the electrical box with it that holds the relay and caps. Was told by the local agents that any 1HP box will run this compressor. So I used a box that holds a 90-110mfd Starting Cap, 10mfd Running Cap and a 3ARR3A4AG3 relay.

When I tried to start it the compressor then hums and after 2 or 3 seconds the overload kicks out. Now on Embraco's website they say it must use a 88-108 start cap and 15mfd run cap and a 3ARR3B6V3 relay. Can this be the problem? Checked compressor for shorted windings (to earth and to eachother) but it seems fine.Amps measure about 30amps for that 2 seconds before it kicks out.

Any ideas please :confused:
Hi :
you should try manufacturer advice !!
but also check your connections .
good luck:)

[fredser]

Yeah was hoping to do that but they wont sell me the box seperate from a compressor.

[monkey spanners]

Measure the current in the start winding feed when it is trying to start, no current means no feed, measure the current in the start cap wire also, no current again means it is not in circuit during starting conditions, if its a potential relay they need to be mounted the correct way up, you can also often take the cover off to see if it is switching, failing that you could use a switch that you operate to replace the relay to see if the compressor will then start and then get a suitable relay, the capacitors are not that different in size.

Above all, re check all the connections. Pin configuration may be different between the two manufacturers.

Jon

[fredser]

Thanks spanners will give that a try.
So if the relay must be mounted in a certain way - and the the box has been loosened and laying on its back - the relay wont function?

[monkey spanners]

Just found this,

http://pdf.directindustry.com/pdf/ge-industrial/3arr3-type-potential-relays/9148-66151.html

It states under 'mounting' that the relay is calibrated for its intended mounting possition.
I tend to fit like for like in the same way as the manufacturer if possible.

Jon :)

[nike123]

Running capacitor cannot be 30% smaller than what it is manufacturer recommendation. Its tolerance is max 10%.
Your first concern is to use correct run capacitor.
Start relay must be able to hold long enough that compressor accelerate to full speed. That is about 3 sec.
If you are not sure if relay is OK, you could use switch instead of relay and do not hold it closed more than 3 sec, after connecting power to compressor.
If all capacitors are OK and this manual start is not successful, your compressor is faulty or overload relay is faulty (assuming that wiring is done correctly and power supply voltage is within limits and there is no obstructions in refrigerant system).

[fredser]

Thanks Jon for link - very helpfull.
And thanks Nike - ill replace the running cap with the right one. Been looking for the right relay today without luck. See that the pickup voltage of the one im using now is way higher (332V against 222V)
Gonna try and start it with a manual swith tommorow.

Thanks for all the replies guys.