Centec

I finally got the Bantam of the pallet and a new switch fitted so i have a reverse now, on to the Centec 2B not so good when I switched on the main motor the lights went out after this happened a few times I thought sod this, so of came the motor and of I went to Lincs rewind to get it checked and it turns out the motor is OK, so back to the mill I wired the motor direct from the converter and it only just got it going but after a few test starts it tripped the lights again, so now need to work out what's the best thing to do this is where some good advice would be handy, the converter I use is a Clark PC180 1.75hp I think the motor is too big for it so think I will have to look for another one, you cant read any of the info on the motor plate so I don't know how big it really is but I have another three phase motor but its 2.2kw 3hp 2800rpm so it too power full and too fast but the converter does run it ok, I wondered if a .75hp 1400rpm three phase would do the job, any advise would be gratefully received.

Regards Alan.

Be aware that invertor drives are prone to tripping standard RCD devices - in industry 'delayed action' RCDs are used to avoid this. Your problem might not be realted to incompatibility between motor and invertor.

Edited By David Jupp on 23/02/2013 19:51:46

You might get help here.

hi - is the starter capacitor too small? Sounds suspect to me.

Its three phase fizzy, don't think it has a capacitor unless its in the motor its self.

Al.

You need a motor of 1.75hp or less from what you say about the converter. A 2800 rpm motor is down on torque, and will have a very high starting current, specially starting under any load, a 4 pole / 1450rpm motor is much better adapted to your milling machine, I would suggest that1.5hp would proberbly be a bit better than .75 hp you mention.

You could always light the candles before you press start, then you'll be able to find the circut breaker.

Ian S C

I think the Clarke converters are all eiother capacitator or rotary, not inverters. I think for the rotary ones the Machine Mart cat advises using one of TWICE the nominal motor HP.

Neil

Hi Alan,
There are too many unknowns in your problem.

1 You say it trips the lights. Is it connected to the lighting circuit rather than its own MCB on the consumer unit or plugged in to a socket on the one of the ring mains ? Is the tripping being caused by over current (Tripping an MCB) or by earth leakage (Tripping an RCD) ? ( I suspect you mean that it is tripping the main RCD which will cut power to all circuits but this is only an assumption.)

2 I cannot find any information on the Clark(e) PC180 but the Clarke PC 20, 40, and 60 are the type of converter that uses capacitors to provide phase shift. Is it this type ?

3 Although you cannot read the data on the motor the dimensions should give you some idea of its ratings by comparing it with motor manufacturers data.

If the PC180 is not an inverter (which would give you the option of variable speed.) then I think replacing the motor with a single phase one would be the best option.

Les.

Once again thanks for the reply's guys it all helps make the decision, Ian the converter will run up to a 1.75hp motor after cleaning the data plate from the old motor with some braso i can just make out that it's a 1hp motor so i think that's how I will go, Les your right in thinking that it trips the main breaker should have made that clear sorry for that, the PC180 is a converter it's been rebadged I bought it around a year ago, at the old house I could get the mill going by pulling the drive belt at the back of the mill to help it get going the new house must have a more sensitive breaker because it trips straight away, I will be looking for a 240 1400rpm 1hp motor any recommendations on a good source to buy one.

Regards Alan.

Alan,

When I bought my Centec 2A it came with a Clarke single phase motor which hasn't given me any worries.

Martin P