VFD wiring assistance

[ronan]

Seems really strange that reverse isn't working in that case, have you tested that 12v is getting to the screw connection for reverse. Not doubting that it isn't as you seem to have tried everything already but really curious why this doesn't work.

Your guess is as good as mine at this stage.

 

[Seadog]

It sounds like a faulty unit. There's so little to configure. Good luck tomorrow.

 

[R-D-R]

Definitely sounds like something’s up with the inverter. I would swap one of the motor leads around to force it to reverse when in forward just to make sure the motors not acting up. If it reverses I would then (assuming no warranty) crack the VFD open and start tracing the reverse feed back from the contact with a meter.

Had a look at your manual it does look pretty straight forward so should be working as far as I can see.

 

[Dcal]

Before you give up on the inverter, do you still have the original wiring on the mill?

As it was a three phase machine it should have the wring and switch to run the motor both ways.
As R-D-R says it's just inverting a couple of motor leads and that can be done with a switch or relay down stream of the inverter.

That's how I wired my 3 phase drill. I just use the inverter for speed control and on off. Reversing is done on the drill switch and wiring.

 

[ronan]

Right, i asked on other forums and a chap in the UK came up with a solution. Apparently he works at this sort of thing, plc's, vfd's etc. He said that the rev had also to be connected to the start terminal, which i sort of knew already, and had tried this with a length of wire. All this did was reverse the direction of rotation of the motor. No good.

So what he said i should have done is to connect rev to start using a diode. I thought it was worth a shot so scavenged one out of an old radio, amazingly i could not find one in the radio, apart from an LED, so thats what i used.

I connected the two sides of the switch using the LED and tried it, works perfectly turn the switch one way, motor goes clockwise, turn it the other and it goes anti-clockwise.

So there you are, thanks for the answers and suggestions.

 

[carbon]

Good to know you have it working, shame they don't put that in the manual

 

[ronan]

Good to know you have it working, shame they don't put that in the manual

Thats what i thought. But i think it is a case of if you have to ask, you should not be installing it in the first place.

 

[daleyd]

Hi ronan glad you got it sorted but I think there was some confusion as to what the problem was - I was under the impression it wouldn’t run backwards at all?

The diode does the same as having an extra contact on the reverse switch in effect - it allows the signal to pass to both run and Rev in the reverse position and only to run in the “Forward” position - if you wired it up without the diode and with only one contact then when you select run it would also put the signal back to the Rev contact. Using a diode is commonly used to avoid this happening.

 

[ronan]

Hi ronan glad you got it sorted but I think there was some confusion as to what the problem was - I was under the impression it wouldn’t run backwards at all?

The diode does the same as having an extra contact on the reverse switch in effect - it allows the signal to pass to both run and Rev in the reverse position and only to run in the “Forward” position - if you wired it up without the diode and with only one contact then when you select run it would also put the signal back to the Rev contact. Using a diode is commonly used to avoid this happening.

I probably did not explain it very well. i could get the motor to run in either direction. If i connected start to rev with a short piece of wire it would run the opposite direction to what it did if the wire was not there, but no matter which direction i turned the switch, it spun in the same direction. I had a bit of a mess around with it a few minutes ago, i also tried the diode from the jog terminal to start, and the jog function works fine now too.

So now i can run the motor in either direction with the twist of the switch, and run the motor at either 5 or 10 hz in jog. Great for clocking up circular work.

 

[Seadog]

You'd have saved us all a lot of head scratching if you'd said all that earlier on. I always believed you had the switch wired incorrectly, or it was not suitable for the way in which you were trying to use it, hence my 'diagnostic' questions. I'm glad you got it sorted in the end though.