3 phase motor issue

[agrimog]

check your voltages, and check your supply cable diameters, sounds like a voltage drop under load

[Big J]

There is no voltage drop anywhere on the system. Well nothing outwith of tolerances - at every point the reading it just over 400v. Cabling is overspecced - we needed 2.5mm steel wire armour but put it 4mm to be safe.

 

Thanks for the contact Mike - I shall get on the phone to them tomorrow.

 

Thanks for all the other advice and help. I will try everything listed.

[Big J]

Forgot to say the the supply is fine - we run an edger off the same board which has a 21 kw main motor and more powerful feed motors and that is fine.

[cornish wood burner]

Forgot to say the the supply is fine - we run an edger off the same board which has a 21 kw main motor and more powerful feed motors and that is fine.

 

Morning BigJ

Presumably each machine will have its own breaker in the board so most likely supply problem would be in the individual mccb. Had a few of those go down but more contactors than mccbs.

[Big J]

Morning BigJ

Presumably each machine will have its own breaker in the board so most likely supply problem would be in the individual mccb. Had a few of those go down but more contactors than mccbs.

 

I am confident that there isn't a supply issue. The electrical supply to the machine is brand new and professionally installed. No issue with voltage drop anywhere on the line or anywhere on the machine.

[farmer rod]

Forgot to say the the supply is fine - we run an edger off the same board which has a 21 kw main motor and more powerful feed motors and that is fine.

 

Hi Big J,

 

How are you measuring the current? If it an ammeter on the machine , can you change it to measure on different phases?

 

And also, Does the sawing motor stall or trip out?

 

Hope you get this sorted, and just a few random thoughts, but it would be another plus for Arbtalk if we came up with the answer!

 

Rod

[Billhook]

I suppose that you could eliminate all the supply/breaker/cable issues leading up to the motor by borrowing a tractor driven 3 phase generator and connecting it to the machine directly.

[farmer rod]

Just another random thought,

 

Is the motor revolving the correct way, Having not seen the machine, I might be asking a daft question, but for instance a shaping machine has a linkage that provides a uniform force and speed on the work stroke, and a quicker return stroke.

[Big J]

Ammeter on the machine, testing the different phases. Amps measured at the point where the power comes into the machine and then at the motor as well.

 

I do have a large generator in the yard for powering my sawmill, but it is largely unmoveable. I'm waiting to see what the company say about sending an engineer over, because I think there isn't much left that we haven't ruled out apart from faulty motor or electronic fault.

[Big J]

Just another random thought,

 

Is the motor revolving the correct way, Having not seen the machine, I might be asking a daft question, but for instance a shaping machine has a linkage that provides a uniform force and speed on the work stroke, and a quicker return stroke.

 

The motor is running the correct way, as best I can tell. Switching the phases round to try to change the direction of rotation only results in a phase fault showing and no operation of the machine at all. That being said, the motor provides a steady RPM and with the fly wheel and conrod system on it, I don't think that it would make any difference to the machine if the motor spun the other way (assuming the power output was the same in both directions).