star delta - generator

[Simon-0116]

Got star delta motor new installation, when goung into run just dies, dosrnt trip over losd, as if contactor not holding in on run. Wrong wiring diagram eith pannel, u1 goes u2, v1 to v2, w1 to w2 on motor windings. Running of a generator, 200kva, 50 kw motor, so man enough. Pannel firm say generator maybe lossing voltage when coming in to run mode. Only tested voltage 238v, 408v when running, never tried under load, any ideas

 

[Pete999]

Sorry mate your post is very confusing, a diagram and a better description of what you have may help someone give you advice.

 

[Bobster]

So whilst the motor should be running in delta, the windings are configured L1= U1,U2 L2=V1,V2 L3= W1,W2?

If so it's pretty obvious why it isn't working.

 

[Knobhead]

I despair. I really do.

 

[plugsandsparks]

Double check the drawing, and don't assume the motor is dead when in run as it looks like its live but not as we know it. I would look very closely at your U2,V2,W2 connections. good look

 

[davesparks]

I have very little knowledge of motors (I can see the obvious one as pointed out above though) but generators are familiar territory.

So, what does the generator do while this is happening? Does it slow down, chuck up a cloud if black smoke, show up any warnings?
Is this the only load on the generator or is there a decent load on it before this motor starts?
Have you tried it with the generator unloaded aswell as under a decent load?

 

[ian.settle1]

I despair. I really do.

Have to totally agree Tony

 

[hearts]

I was 4th electrician called to a job where 2 expensive pumps had burnt out. they were wired pretty similar to above and were single phasing. no-one noticed wiring !!

 

[Simon-0116]

I have very little knowledge of motors (I can see the obvious one as pointed out above though) but generators are familiar territory.

So, what does the generator do while this is happening? Does it slow down, chuck up a cloud if black smoke, show up any warnings?
Is this the only load on the generator or is there a decent load on it before this motor starts?
Have you tried it with the generator unloaded aswell as under a decent load?

hi not very good at explaining, 6 terminls on starter, 6 on motor. on motor proved windings labelled correctly, by continuity test u1 - u2, v1 to v2, w1 to w2 are all circuits. starter has 6 terminals, no labelling, manufacture says 2 possible combinations, u1, v1, w1, then w2, u2, v2. or a different combination of the 2's. tried both but wont work.

 

[Simon-0116]

only load on gen, no change of engine noise, smoke, suggested could be a volt drop when changing over?, never checked it with meter / or on gen volt meter, going back so will check, thanks

 

[davesparks]

No change of engine noise suggests no change in load, it's not an exact measure but I would expect to hear a change if a 50KW motor suddenly cut out.

 

[Lucien Nunes]

Edit: just saw recent post. That looks OK as given, or V2, W2, U2. I think we all thought you meant U2, V2, W2 (which is open-circuit to all lines) and the other three are the wrong sequence and will cause single-phasing.

 

[davesparks]

Pass me some of whatever you've been drinking please?

 

[Simon-0116]

Edit: just saw recent post. That looks OK as given, or V2, W2, U2. I think we all thought you meant U2, V2, W2 (which is open-circuit to all lines) and the other three are the wrong sequence and will cause single-phasing.

thanks, wrong wiring diagram with panel so didn't help ,i'm only used to connecting up, not got any knowledge with fault finding, tracing wiring through starters. hopefully right diagram and if manufacture marked terminals would be easier. is there a sequence ie L1 u1 and say V2, L2 v1 w2, L3 w1 v2, so I could trace wires back, like on a line drawing. or is it just the order of the manufacture.

 

[plugsandsparks]

If you suspect either the panel is wired wrong (possible) or the drawing is wrong , then I would identify the MC, DC and SC contactors and just follow the wiring to the terminal blocks at the bottom. There are plenty of star delta wiring diagrams on the internet which will show how to connect the 6 motor wires. As for the motor, hopefully that is labelled correctly otherwise again you will need to test that out. Coincidently I am just about to leave home to connect up a 90KW jobbie, hopefully it wont go bang. lol

 

[Simon-0116]

Looked at diagram I had in van and was same, went back last nite 2 of us, I stoped at gen, taking 415v ,160a, start, when drops into run voltage goes to 385v, engine changes tune bavk to 415v, fans dropping out due to volt drop ??? Cant be anything else. Hope your motor when well, thanks

 

[Simon-0116]

Quick update, thanks for the positive comments, generator firm came out swapped avr? Still wont start the fans, took generstor away ( stamford) came back with a meccalte, adjustable avr? Fires up and runs the fans a treat, thought I was going mad, just very grey now

 

[Simon-0116]

Why can't I add pics????

 

[Knobhead]

Because you're not trusted.

 

[Bobster]

Just host the photos on photobucket or similar. Then just embed a url.

 

[Simon-0116]

Why not

 

[plugsandsparks]

Looked at diagram I had in van and was same, went back last nite 2 of us, I stoped at gen, taking 415v ,160a, start, when drops into run voltage goes to 385v, engine changes tune bavk to 415v, fans dropping out due to volt drop ??? Cant be anything else. Hope your motor when well, thanks

A couple of minor adjustments on site and transitioned really sweet. I have a client who likes generators but am curious as to why the drop out, or what was dropping out as 385v I would have hoped the control ccts were still good. Was the AVR actually " cutting" the output and hence drop out or what?

 

[Bobster]

Avrs are pretty slow acting, especially to a rapid change in load. E.g a poorly set up open transition star delta starter.

In short the avr could have stalled the genny?

does the new one have an avr installed or a more modern faster acting davr?

 

[BeerSpark]

Glad you got it sorted. If in doubt, draw it out.