Bridgeport M VFD install

Mgdoug3

Mgdoug3

Registered
Registered
Joined
Feb 2, 2020
Messages
146
I have a VFD on my Clausing lathe and it works great. I just picked up a Bridgeport and am not a fan of the static converter. I have a VFD on the way but I wasn't sure how to wire it since the mill also has a 3 phase motor for the power feed. Do I wire both motors together or is it even possible?
 
I wouldn't. I would probably keep the power feed running off the static converter, awkward as it seems
Curious to hear what others would do
-Mark
 
I'm no expert on VFDs, but I don't think that will work. Essentially you have to go from the VFD to the motor, with nothing in between if you don't want problems (like a fried VFD). In that kind of scenario I'd ditch the static and VFD and get an inexpensive RPC and be done with it. When I was just looking to run one machine I was going to get a North American Rotary 5hp setup...$470 on Amazon as of a few weeks ago. A decent VFD in the 2-3hp size is close to $300 and the cheap ones from Amazon and eBay have all sorts of issues.
 
Don't fix it if it ain't broke, I always say LOL. I also have been known to do things cheaply with what's on hand, and since you already have a VFD on the way you can power up with a minimum of fuss and cost
You don't want to risk blowing the VFD output stage by trying to power two motors. Too much chance of voltage transients
-M
 
Power feeds on the older Bridgeports are often DC drives and run off of a separate transformer single phase that is powered by two of the phases or 120VAC. So the VFD is a direct connect to the motor and you bypass the standard switch gear/contactors. Usually I recommend 3 wire control which is momentary switches for run and stop with a sustained switch for reverse. Alternative is an RPC. Static converter could be used but you need to make sure the drive is not powered by the wild leg.

If the drive motor was 3 phase AC it would need to be driven by a separate power source, in that case you would be better off with an RPC.
8F Power Feed.jpg
 
I looked at the motor tag on the power feed and it said 3 phase and 1/8 hp. I'll double check but I assumed it was running off 220v.
 
mksj said:
Power feeds on the older Bridgeports are often DC drives and run off of a separate transformer single phase that is powered by two of the phases or 120VAC. So the VFD is a direct connect to the motor and you bypass the standard switch gear/contactors. Usually I recommend 3 wire control which is momentary switches for run and stop with a sustained switch for reverse. Alternative is an RPC. Static converter could be used but you need to make sure the drive is not powered by the wild leg.

If the drive motor was 3 phase AC it would need to be driven by a separate power source, in that case you would be better off with an RPC.
View attachment 352379
Click to expand...
If he is running a 3 phase motor, it is the old gear driven power feed. Came in 220 3 phase, 220 single phase, and the more rare ones on the gear driven feeds were 120.

My Knight #2 has a 3 phase motor for the spindle as well as one for the gear driven power feed. I run both of them on a solid state phase converter with no issue. Never tried to run two motors off of a VFD, not sure if I ever would either.

Jon
 
I took the drum switch apart and wired the power feed motor separately to the static converter box. It works just fine. I think the drum box is making poor connections because wiggling the switch changed the speed of the motor. VFD should be in tomorrow so I'm doing away with the switch.
 
Last edited:
VFD came in and got it installed. It works much better now. The motor seems much happier now too.
 
You must log in or register to reply here.
Back
Top