3 phase motor issue

[Big J]

Can you eliminate absolutely all switchgear and go to 'Stone Age' basics- drive the motor direct from the supply board, preferably through your edger's MCB and supply line (known to be good). If the flywheel isn't too massive I would imagine the machine would start up directly on Delta. You'd then have a definitive answer of control issue or motor issue.

 

Brand new control gear is in no way a guarantee of good working order. Far from it. We were foxed for a while with a duff breaker feeding my Logosol moulder. The thing looked good for continuity and behaved until the machine was fired up and reasonable amps were flowing.... Can you substitute another breaker at the wall?

 

The flywheels are pretty massive. Probably 3-400 kg between the two (one on each side of the machine for each con rod).

 

No way of removing the electronics I think. It's a fairly complicated box, when you open it up. Either way, it shouldn't be defective. The machine is only a month old, hasn't worked properly from the start and with the company having sold another 16 frame saws this year alone, there should be no issues.

[cornish wood burner]

The flywheels are pretty massive. Probably 3-400 kg between the two (one on each side of the machine for each con rod).

 

No way of removing the electronics I think. It's a fairly complicated box, when you open it up. Either way, it shouldn't be defective. The machine is only a month old, hasn't worked properly from the start and with the company having sold another 16 frame saws this year alone, there should be no issues.

 

That's a lot of weight to start swinging. Perhaps the electronics form a speed controller to limit start up current. Our spend controllers have parameters to input to modify startup as well as running speeds. Wrong parameter somewhere perhaps if that's what you have?

[Big J]

That's a lot of weight to start swinging. Perhaps the electronics form a speed controller to limit start up current. Our spend controllers have parameters to input to modify startup as well as running speeds. Wrong parameter somewhere perhaps if that's what you have?

 

I'm not sure. The 15kw motor doesn't seem to struggle to start them, and the star phase was preset from the factory at just 3 seconds. We tried fiddling round with it from nothing to 30 seconds and it made no difference. The amp draw was good and consistent with what you would expect on start up - only goes downhill when wood is introduced to the blades. There is no binding of any significance to slow the blades either as there is next to no heat buildup in the blades.

[cornish wood burner]

I'm not sure. The 15kw motor doesn't seem to struggle to start them, and the star phase was preset from the factory at just 3 seconds. We tried fiddling round with it from nothing to 30 seconds and it made no difference. The amp draw was good and consistent with what you would expect on start up - only goes downhill when wood is introduced to the blades. There is no binding of any significance to slow the blades either as there is next to no heat buildup in the blades.

 

Not quite the area I was meaning. That sounds just a basic timer to change from star to delta. I was thinking you might have an inverter control in your electronics to help starting. Some of the ones I have come across have all sorts of ramp up, ramp down, current control etc etc. In fact a whole page of parameter to settings.

Have you tried running for a while before introducing the wood.

[Big J]

Not quite the area I was meaning. That sounds just a basic timer to change from star to delta. I was thinking you might have an inverter control in your electronics to help starting. Some of the ones I have come across have all sorts of ramp up, ramp down, current control etc etc. In fact a whole page of parameter to settings.

Have you tried running for a while before introducing the wood.

 

Ah OK. Not sure about that. The electronics aren't something I have the means to explore, on account of the instructions being in Polish, and electronics not being something I know much about. As far as I am aware, and from observing the current draw, I think that the starter is a simple star delta start.

 

I have put about 20 logs through it, so it has on occasion been run for some time before another log is introduced. Of those 20 logs, only about 3 or 4 have gone through without it stalling at some point.

 

J

[cornish wood burner]

Ah OK. Not sure about that. The electronics aren't something I have the means to explore, on account of the instructions being in Polish, and electronics not being something I know much about. As far as I am aware, and from observing the current draw, I think that the starter is a simple star delta start.

 

I have put about 20 logs through it, so it has on occasion been run for some time before another log is introduced. Of those 20 logs, only about 3 or 4 have gone through without it stalling at some point.

 

J

 

And you are absolutely certain the delta contactor is good under load

[Big J]

It seems to be. The current reads about 50 amps for a second on star start up, then settles down to about 10 amps. There is then a 19 amp spike and it settles down at about 13 amps on delta with no load.

 

I shall have a look tomorrow at the delta contactor to check.

[billy_wizz]

Can you run it with just 3 blades to see if it makes any difference as if it works as should with 3 then it might be part of the control gear somehow pulling it back

[Big J]

Can you run it with just 3 blades to see if it makes any difference as if it works as should with 3 then it might be part of the control gear somehow pulling it back

 

I could, but the machine would be utterly useless on 3. It's on 10 at the moment and will be running on 15 shortly. I think it can only be the control gear, but diagnosing which bit is very tricky.

[Graham w]

I could, but the machine would be utterly useless on 3. It's on 10 at the moment and will be running on 15 shortly. I think it can only be the control gear, but diagnosing which bit is very tricky.

 

i would look at upgrading the motor to somewhere around 30kw if you are looking to increase output. you can find used motors and starter boxes for very little cost alternatively a new brook crompton setup will cost a little over 2k