11.8amp motor power supply.

by **fairleyforge** » Sun Dec 30, 2007 6:51 pm

I have bought an air hammer that has 11.8amps on the plate. I had hoped it would run on 13 amp supply but just keeps blowing fuses.
Do I need a 16 amp supply? and if so do I need to worry about overloading the motor?

Thanks

John

by **333rocky333** » Sun Dec 30, 2007 11:58 pm

Is it definately 230 volt, should not really take more than the plate rating unless you are seriously overloading it.

Would not think they would sell many if it was 230 v and more than 13amp.

As no one would have a blue 16 amp socket unless they were on site or something then 110 would proberly also be available and preffered.

What is make and model

by **fairleyforge** » Mon Dec 31, 2007 6:41 pm

Slipped belt off motor and it ran straight of. reconnected and all works fine, must have been mechanical prob.

Thanks

John

by **ericmark** » Mon Dec 31, 2007 7:04 pm

I think we are looking at inrush?
When any motor starts it uses a lot more power than when running, fuses and MCB's are rated to allow for this. In fuses we have motor rated with an M and second figure and with MCB's type 4 or D depending on age. There are systems to help this form the star delta on three phase supplies to auto transformers softstarts and inverters. As to which to use is dependent on how and where it is used. Yes a 16 amp supply will help. But also a motor rated 13 amp supply could also work. One problem with motor rated supplies is the earth loop impedance required also changes it is not as simple as just changing the MCB. If it has one location then upgraded supply may be the answer but if used in multi locations then a softstart unit may be required. Softstarts and Inverters both allow the item to start slowly so reducing the inrush but inverters also allow speed variation and are more freely available. you really do need an industrial electrician to advise. The house electrician will not be familiarly with these specialist items. Same with suppliers you need someone who supplies industry not the domestic trade to advise you.

All best Eric

by **fairleyforge** » Wed Jan 02, 2008 5:15 pm

thanks EricMarK,

The machine is stationary in my workshop and although I have been able to tease it into action it still blows fuses on start up. From your advise I think the best course of action would be a dedicated 16 amp supply to the machine. would you agree?

Thank J