New Compressor tripping relay

[Grrrmachine]

MY new 4hp compressor's keeps tripping the breaker in my garage; as soon as you turn it on, not even a kick from the motor, just instant power shut-down.

I brought it indoors and plugged it into the kitchen cooker ring (dedicated 20A) and it fired up straight away. However, I was under the impression that all 230V compressors should be able to start up from a 16A ring.

I've done a bit of reading, and I'm wondering if the fact that I'm using B16 breakers is the issue here, and would a C16 help, or do I have to completely rewire the garage?

 

[brightspark]

MY new 4hp compressor's keeps tripping the breaker in my garage; as soon as you turn it on, not even a kick from the motor, just instant power shut-down.

I brought it indoors and plugged it into the kitchen cooker ring (dedicated 20A) and it fired up straight away. However, I was under the impression that all 230V compressors should be able to start up from a 16A ring.

I've done a bit of reading, and I'm wondering if the fact that I'm using B16 breakers is the issue here, and would a C16 help, or do I have to completely rewire the garage?

depending on the wiring if its wired in 2;5mm cable. biggest breaker would be 20 amp c type if its in 4.0mm a 30 amp mcb .

the starting load on a 2.5kw 3 hp is 55 amps so a 4 hp will be higher so theres your problem i would have thought a 4hp would require a 30 amp supply

 

[eil]

I have a 4hp motor on a comp and it takes 70amp on start.

 

[Grrrmachine]

Like I said, it started up on a 20-amp ring, so I'll try a C16 breaker first and if that doesn't work, I'll redo the wiring and try a 20A breaker. My trouble is that my garage is part of a communal series, so that each garage has its own meter and fuse but the whole block also has its own fuse, and it tripped that one before it tripped my own garage fuse. So now the whole garage block is without power, and I don't have a key to the fuse cupboard....

 

[Grrrmachine]

So this thing will start on a B20 ring, but not on a B16 ring, even though the plastic cap that covers the start switch says "MAXIMUM 16A."

I took the shroud off the motor (because there's no specification plate) and saw two capacitors; a 65uF/450V Run Capactor, and a 200uF/250V Start Capacitor. Motor is rated 3.1kW (4hp).

Is starting this off a 16A circuit too optimistic? Would increasing the size of the Start Capacitor help at all?

 

[brightspark]

So this thing will start on a B20 ring, but not on a B16 ring, even though the plastic cap that covers the start switch says "MAXIMUM 16A."

I took the shroud off the motor (because there's no specification plate) and saw two capacitors; a 65uF/450V Run Capactor, and a 200uF/250V Start Capacitor. Motor is rated 3.1kW (4hp).

Is starting this off a 16A circuit too optimistic? Would increasing the size of the Start Capacitor help at all?

just change the breaker to a type c from the type b

 

[Grrrmachine]

I would if I could, but I don't have access to the communal garage block fuse panel, and that's the one that's tripped, not the one in my own garage. Effectively, it's knocked out the power to 10 garages rather than just my own.

 

[brightspark]

I would if I could, but I don't have access to the communal garage block fuse panel, and that's the one that's tripped, not the one in my own garage. Effectively, it's knocked out the power to 10 garages rather than just my own.

basicaly your stuffed if u cant gain access to change the trip to a type c type . a b type breaker is rated to trip at faullt currents rated 3 to five times the rated current. a c type breaker is rated 5 to ten times the rated current , example a 10 amp b type breaker will trip at 30 to 50 amp and a 10 amp c type 50 to a 100 amp

 

[Grrrmachine]

That's good to know. I'll find the man responsible and find out about these fuses; it shouldn't be too much of an issue to have a higher one put in, since these garages were built for the workers of the State Energy Company (gawd bless Communism) so all the old boys around here are ex-electricians, gas plumbers and the like.

Shame there's no sort of "power buffer" I can rig up though.

 

[Troll]

I have exactely the same problem, I just moved house the this being a newer house has circuit breakers, and the garage is on a 16A MCB, which trips when the compressor starts. All ok when plugged into the kitchen which is on a 30A MCB.

guy's in another forum also suggested to change to a type C 16A MCB, so I will try that and report back.

Mark

 

[Grrrmachine]

I've just tried it. My washing machine had its own dedicated ring, with a B16 relay. I just swapped it over for a C16, and the compressor fired up on it no problems at all.

Now I just need to find out how to get the same relay installed in the garages.

 

[eddie49]

Increasing the size of the start capacitor ( which, at 200 uF, is already large ) would make the problem worse. As well as the breaker-type issue, other factors involved are: the compressor is new, and will be "tight", and it's winter, and you're in Poland, so the oil will be cold and thick.

 

[Grrrmachine]

The compressor's in my flat at the moment, warming up. I understand the tightness issue alright, but the oil won't be that thick. Trouble is, unless I wrap it in blankets or something, I can't really run it in so that it's not so hard to start.

Thanks for the info regarding the capacitor though.

 

[Robotstar5]

unless I wrap it in blankets or something, I can't really run it in so that it's not so hard to start.

Go for it, at least it will give the neighbours something to talk about..."what the devils he doing next door?"

 

[Grrrmachine]

One month later, things have warmed up, and I've finally managed to sort out the electrics. The garage block was running off a B20 breaker, which I've since swapped for a C20 for the whole block, as well as a a C16 inside my garage. Compressor fires straight up with no problems. Thanks for the help, everyone.