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VFD ground?

1K views 13 replies 6 participants last post by  justthecowboy 
#1 ·

Hello, hopefully someone here won’t mind answering a question from a non electrician.

I bought a jointer for my shop and took it apart to get it home, I figured if I put all the electrical back the way it had been everything would be fine.

As I started putting it back together I noticed the ground from the power cord had never been connected and that didn’t seem right to me.

Attached is the photo of the original. The red, black and white on the bottom left are power coming in from a 50 amp 240v single phase circuit. The red wire in the front is connecting the 12v slot on the VFD to L1 on the switch and the blue wire in the front is connecting the FW slot on the VFD to T1 on the switch. The motor (three phase, 2hp, 5.2A) has three wires going to T1, T2 and T3 on the VFD. It is setup so the VFD will not normally need to be touched but will just act as a phase converter with the main jointer switch turning everything on and off. The VFD is a Teco FM50 Fluxmaster if that is helpful.

Isn’t there supposed to be a ground in here somewhere?

Lastly, while I’m here the wiring from the switch to the motor and the motor to VFD is all 12 gauge, is that big enough for this?

Thank you,

David


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#4 ·
The other end of the wire with the red white and black was a 4 prong plug (permanently attached, not a screw together replacement type) so I would think that white would have had to go back to the neutral blade on the plug and from there back to the neutral bar in the breaker box.


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#5 ·
Can you find /get a wiring schematic?

I had a similar problem after replacing a multi position switch on a combo machine.

Could not find where a loose wire went...

Called my EC friend who sent his trouble shooting electrician over.

Inside of 5 minutes he solved the issue...
 
#7 ·




The jointer is a medium duty, 12 inch Northfield, built somewhere between 1930 and 1950, I was not able to find a serial number, even after talking to Northfield.

I doubt there is any kind of real wiring diagram, it looks like most of this was redone at some point, some of the wires from the switch go nowhere and some of them are just spliced together with electrical tape. I’m realizing I probably want to put in a new safety paddle switch and a new wire from the switch to the VFD while I’m at it.

If this gets too involved I may need to hire the electricians who wired the shop to come out again, I was hoping I could sort this out on my own. The seller turned it on for me before I took it so I know this setup works, I’m just not sure if it’s grounded.


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#12 ·
Ughh, what a mess!

That VFD is Australian. They only have 240 volts down there so L1 and L2 is the line- 240V. Further, one side of their 240 is a neutral just like one side of our 120. So down under, L1 is the hot, L2 is the neutral and L3 is ground.

When used here it's correctly connected with 240V on L1 and L2. L3 is still the ground so it should have a green ground on it connected to the ground prong on the plug. The white wire color suggests that it is the neutral which is not correct.

Easy enough to change.

-Hal
 
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