Author Topic: 1980's Planer - keeps accelerating until motor cuts out/  (Read 281 times)

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Offline PlanerProblems

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1980's Planer - keeps accelerating until motor cuts out/
« on: May 22, 2022, 05:25:10 pm »

I have a 1980s Wadkin Bursgreen 3 phase planer that I’m trying to run off a single phase power supply. To achieve this, I have wired my single phase power through a 35amp fuse in my garage, into a Transwave static phase converter. I’ve run a cable from this converter into my planer.  Here’s a photo of the starter:

The brown, red, and yellow cables at the bottom of the photo are coming directly from the converter, as is the Earth cable grounded in the top right.

The planer has two motors, one for cutting (3hp) and one for feeding (0.5hp).

The three pairs at the top of the photo are (brown & black), (brown & blue), and (brown & brown). One brown cable from each of the three pairs is connected directly to the cutter motor, as is one of the Earth wires grounded in the top right of the photo. The black, blue and other brown cable that makes up each pair goes to the feeding motor. To isolate the problem I’m having, I’ve disconnected these three wires.

So the current set up is: the brown, red, and yellow cables at the bottom of the photo come directly from the phase converter, the thick Earth cable at the top right of the photo also comes from the phase converter. Then their three corresponding brown cables at the top of the photo go to the cutting motor, and one of the Earth cables in the top right of the photo goes to the cutting motor too.

Now here’s the issue, while I was wiring this in, everything worked correctly. I started the planer and after 1-2 seconds the “Boost” light on the phase converter would switch off, meaning the motor had received enough power and was running correctly. But I think I did something to either a cable or the starter when I was screwing on the front panel, because when I start the planer now, the “Boost” light on the phase converter stays on, and the motor keeps accelerating until it cuts itself out after 30 seconds (the motor overheats). I’ve tried the following:t

•   Checked every wire for snags/cuts
•   Rewired each brown wire at the top of the photo directly into the motor to ensure none are damaged
•   Checked the connectors in the starter to make sure there’s no corrosion/that they’re contacting correctly
•   Disconnected the three input wires at the bottom of the photo and turned on the phase converter, tested with a phase tester, they all have power in them
•   Reconnected the input wires, and then disconnected all wires from the top of the photo and used a phase tester on each, there’s power in all of them
•   Reconnected all wires, switched on the phase converter, and before switching on the planer, I tested every connection with the phase converter, every connected registered power when I did this. I then switched on the motor and tested every connection again, this time there was no power in the yellow cable, and no power in the two corresponding wires across from the yellow cable
•   I also tried changing the amp dial on the left of the second photo (0-8 amps), the planer didn’t start at 0-1 amps, but did start from 2-8 amps

Second photo:

I’m completely at a loss as to what changed while screwing on the face plate, I feel like something must have been damaged and the phase converter isn’t registering the fact that the motor has enough power and that it can cut off the “Boost” function, instead it’s continuing to accelerate the motor until it overheats. I can’t work out what it is, there’s no damage to the wiring that I can see and the connectors in the starter look good.

Any advice anyone could give on this would be really appreciated. Thank you!

Offline floobydust

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Re: 1980's Planer - keeps accelerating until motor cuts out/
« Reply #1 on: May 22, 2022, 10:22:01 pm »
Welcome to the forums :)

A good start is having the wiring diagram/sketch, I'm not sure how you're supposed to integrate with the original controls.
What is the switch aux contacts at the right side of the starter? Usually it would be the overload switch or contactor feedback switch.
Casual glance I see it not connected right, it's the small two black wires. One goes to the switch, the other to yellow phase. The other end of the switch is not connected.

"... The motor must be connected directly to the inverter output so controls should not “make and break” the supply to the motor under any circumstances."
To me this says you don't use the old motor starter anyway, it's all up to the inverter in their drawing but nothing about converter connections.
Transwave static phase converter I couldn't see any manuals other than marketing brochures on their website.

Online james_s

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Re: 1980's Planer - keeps accelerating until motor cuts out/
« Reply #2 on: May 23, 2022, 12:11:58 am »
Static phase converters aren't inverters, they just use capacitors to create the necessary phase shift. These days it generally makes more sense to use a VFD even if you don't need the variable speed.

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