Thread: Fitting VFD to Craftsman Lathe

The other members will be able to help you out, but I know you can't break the connection between the VFD and the motor or you will damage the VFD.

Dave

Col, connect directly to the motor. You can do away with the old starter all together.
The VFD will take care of the stop / start and the overload protection.

as dave said no switching between the vfd and motor
i have just fitted a vfd( huanyang) to my hercus 260
set up to run motor at normal speed and change belts as you would normally but you have the option to slow the motor down with vfd
some where i have read that electromagnetic circuit breakers arnt a good idea but some one more experienced will or will not confirm that
i have used oil resistant momentary touch switches to control on / off and forw/rev
biggest trouble i had was getting the parameters all in properly
still having difficulties with the vfd shutting down when under reasonable load
john

Yes I seconsd that - connect direct to the 3ph motor. I don't have a Hercus but I did similar on my Myford. You just bypass the old DOL starter and overload relay, that's all from the olden days now. Your vfd does controlled starting and stopping, has overload protection (plus a read-out diagnostics), forward-reverse, it can run at any frequency you choose while - depending on type you got - can also compensate for torque.

Don't worry where your pulleys are - you can use the pulleys as you normally would, that's a separate thing from hooking up the vfd to the motor. The vfd doesn't care about that.

Only, you need to get yourself a length of shielded 3-core cable between the vfd and the motor, with the shielding braid earthed onto the chassis at both ends. Get that from any trade electrical suppliers.

Make sure you connect the motor correctly - you have either delta or star - I forget which is right. After wiring up, if it spins reverse instead of forward, swap wires on one of the terminals.

What did I tell you Col

Thanks Dave

"The other members will be able to help you out, but I know you can't break the connection between the VFD and the motor or you will damage the VFD."
You confirmed something I read on this Group.

Thanks NCArcher
"connect directly to the motor. You can do away with the old starter all together.
The VFD will take care of the stop / start and the overload protection."

I will by-pass the old gear

Thanks tanii51
"as dave said no switching between the vfd and motor
i have just fitted a vfd( huanyang) to my hercus 260
set up to run motor at normal speed and change belts as you would normally but you have the option to slow the motor down with vfd"
Did you run a remote speed control or use the keypad on the VFD?

Thanks Gunnduit
"Don't worry where your pulleys are - you can use the pulleys as you normally would, that's a separate thing from hooking up the vfd to the motor. The vfd doesn't care about that.

Only, you need to get yourself a length of shielded 3-core cable between the vfd and the motor, with the shielding braid earthed onto the chassis at both ends. Get that from any trade electrical suppliers.

Make sure you connect the motor correctly - you have either delta or star - I forget which is right. After wiring up, if it spins reverse instead of forward, swap wires on one of the terminals."

Good advice and will follow it

Thanks Anorak Bob
Nah.Nah.nah nah Just kidding
Col

col all the controls will be remote just have to get some sheilded cable to complete it
john

Shielded cable isn't essential, just use standard 3 phase cable, available from any electrical wholesaler.

Pete

thanks pete see it pays to ask first actually i was using trailer wiring cable to do preliminary tests
john

Re Shielded Cable


Thanks Peter and John I can use the existing 3 core power cable.
Col

Here's a little primer on cabling with VFDs, sorry it was the best I could find in a hurry and I've only had a chance to skim read it as I need to shoot off, but it seems to cover most points. Note the main point of inducing noise in control cables. In our applications that doesn't tend to be a concern, just use common sense and don't bundle the two together, and cross them at right angles where crossing is required.

Pete

Building a reliable VFD system :: InMotionOnline

I'm no RF expert, but the reason I used the shielded cable as recommended by the manufacturer was that I know the inverter drive in the unit is switching at kHz rates, so I didn't want to interfere with anyone's radio reception.

Yep, you're correct, and using shielded cable won't do any harm unless the capacitance of the cable becomes excessive (extremely unlikely in the installations we're talking about here). However in practice I think a bigger concern isn't interference, but inducing noise in control cables. Laying the cable to the motor next to the control cables may act a little like a transformer, inducing a sympathetic voltage into the control cable. The voltage may be high enough to interfere with the VFD operation. Using shielded cable will normally alleviate that possibility, however it can also be alleviated simply by not running the two cables in close proximity.

Having said all that, if you have shielded cable available by all means use it, but my experience is not to go to any trouble if you don't.

Pete

Thanks to all who gave advice, my Hercus and VFD are up and running..well just about.
The drive fires up and when started the Hercus spindle rotates and can be controlled but much tweaking of the parameters is necessary.

Got the pot and other bits and pieces from Jaycar today so will connect remote tomorrow.

Why didn't I buy a VFD years ago!!

Thank to all for your help
Col