Current rating

[Amp David]

If the maximum power consumption of a machine is said to be 42kVA 3 phase, I worked it out to be around 58 amps. This total current must be over the 3 phases, or am i missing something.

 

[telectrix]

i get 60A per phase

 

[malcolmsanford]

or 60amp over 3 phases .....................so 20amp per phase

 

[Lee89]

If the maximum power consumption of a machine is said to be 42kVA 3 phase, I worked it out to be around 58 amps. This total current must be over the 3 phases, or am i missing something.

I got it to 60.62

I may be well of the mark here, could some one please advise me where I've got wrong, If I have.

I did, 42000 / 692.8 (1.732/400)

 

[Amp David]

20 per phase. Dont know where i got 58 amps from now:dead:

The plate gives max 56 amps at 400v

 

[telectrix]

malcolm, i have to disagree with you here.

42KW is 14kw/phase

I=14000/230=60.86. ( not allowing for power factor.)

 

[malcolmsanford]

malcolm, i have to disagree with you here.

42KW is 14kw/phase

I=14000/230=60.86. ( not allowing for power factor.)

I just saw your post 60amps and thought it might have been in total, then re-read daves post and saw the Kva .........so totally put in my place .......yes mate seems you are spot on.

 

[Amp David]

Cheers guys,

so how come then this machine is happily running day in day out sat on a 32 a c type breaker.

love the quiet days sat at home, it makes up for the days i didn't bother listening at college:freak:

 

[telectrix]

either the MCB has a good overload tolerance, or could be it's contacts are welded together. what size is the cable feeding the motor?

 

[Amp David]

4mm 4 core SWA. Been installed for almost 8 years and doesn't show any signs of overheating anywhere.

Going to go in armed with my clamp meter anyway to check it out

 

[malcolmsanford]

It must be 60amps over the 3 phase, got to be surely. 32 amp C breaker and 4mm SWA, it can't be 60amps per phase.

 

[Amp David]

Malc, this is what i'm thinking. I'm not the brightest spark, but even i thought that lol

I'll find the spec page for the machine and post it

 

[Amp David]

Its the T10M model

 

[telectrix]

then it can't be 42KW. borrow rocker's specs for when you go back.

 

[telectrix]

bet it's a 12kw motor and the 1 has been misread as a 4. that makes sense.