# Recommended vfd for bridgeport



## Cadillac (Jan 11, 2019)

I have a 1hp step pulley Bridgeport that Ive been running a perfect phase solid state converter I think it’s called. It came with the mill when I got it. Was told it will run it but at half the rates power? The mill has a big control box on the back off it with all the contacters and transformers. Big box! Well lately it seems like the contacters are getting loud and I really don’t like the control box and want to eliminate it.
 What would be the recommended vfd for a 1hp Bridgeport?
 I’ve installed three other teco vfds and overall was pretty straight forward. All 3 were teco l510 models I believe. Manual was good and no problems 2yrs in. I’ve heard about derating vfds and I hear yes,no and I really don’t have a clue. Would I need a 2hp to operate a 1hp on 1ph in 3ph out to get the full 1hp rating???
 Is their a better vfd out there for this application? And where other than eBay to get one? Should I be looking into input filters I have not used one and I don’t think Ive had any problems? What’s the problems that would occur? Should I be using a brake resistor? I don’t have any of my setups using a brake resistor. I don’t think the l510 has one. I would like the option of immediate reverse for tapping. 
 Any experience on the subjects would be appreciated. This is where it’s goes over my head


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## CluelessNewB (Jan 11, 2019)

You don't need to derate VFDs unless you are using a VFD designed for 3 phase input with only single phase input.  This is typically only a problem with VFDs greater than 3hp.   The real thing to check is the current (AMP) rating on your motor and compare it to the VFD spec.  If the VFD current  spec is greater than your motor you should be just fine.


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## ttabbal (Jan 11, 2019)

I agree about derating. I use a 2HP VFD for my Bridgeport with a 1HP motor, but that was just because the price was the same and now it's identical to the unit I used for my belt grinder. They are the cheap ones on ebay, I think they were about $70/ea. The biggest thing on the BP was to set the motor frequency setting for 60Hz. The default was 400Hz and the old motor didn't like it. I have a modern motor on the grinder that worked fine that way. 

I don't use brake resistors, I don't think mine have the option for an external resistor. There is something internally, you can set the spin down time. But if you go too low it faults with an overcurrent warning. I find about 3 seconds works well, even at the top speed. This works fine for tapping as I use slow speeds for that and the tool is cutting, helping slow down the machine. 

I haven't needed any filters. I suggest trying one and filtering it if you have noise problems with other equipment. I have computer driven stuff (DRO, CNC, etc.) in the area and it's been fine. Much depends on the quality of your local power and wiring.


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## Bob Korves (Jan 11, 2019)

Agree with the above about de-rating.  However, often the price difference between one and two HP VFDs is very small.  Having a larger VFD will not cause it to use more electricity than the smaller one, and it will be more versatile down the road if you change to a different machine, and will make it easier to sell it when the time comes.  It also will run cooler, which helps it last longer.


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## Cadillac (Jan 11, 2019)

What problems occur with no filter. I’ve always followed instructions on shielded wire and grounds. When I run my lathe it has a  different noise let say when dialing the pod dial for speed control. No side effects other than the slightly different noise more so when going below 60hz. I have it set for only 100hz at max. I have a dro on the lathe and haven’t seen problems. What problems would occur?On my surface grinder I do not have a pod hook up it’s set at 60hz. Motor sounds as a motor does when on. I’m curious as to what noises or effects happen when theirs a problem?


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## ttabbal (Jan 11, 2019)

Noise filters are to prevent high frequency noise from backfeeding into the building wiring. This can cause some electronics to have random issues. Sort of like how the picture on old TVs might get jumpy when someone turned on a vacuum or something like that. In most cases, it's not a big deal. Some devices might have bigger issues. There's really no way to know until you try it. 

For us, people have had issues with a DRO glitching as a result. Proper grounds can help a lot.


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## mksj (Jan 12, 2019)

I do not recommend the generic VFDs on eBay due to lack of support, poor manuals and according to others that work on VFDs questionable specifications. They are the only one where I have heard of DOA or failures. The Teco L510 are a bit better in my opinion, but do not support an external braking resistor. All VFDs have internal braking resistors and some braking ability, just a problem with fast stops with a lot of momentum. You do not need to up-size the VFD if it is rated for the input and amps/hp of the motor. At 1 Hp you can use 120VAC input and the VFD will step-up the voltage to 230VAC 3 phase. I still would use 230VAC input if you have that available. A 2 Hp VFD would need larger input wiring, it needs to be rated for the VFD input not the motor size.

There are other VFDs that are a bit better, but may not be worthwhile. You can use a forward reverse button with 2 wire control to tap, and adjust the speed pot for the RPM. You can use a 3 position selector for For-Stop-Rev. I fusing 3 wire control it is a bit more difficult to implement, I would need to look at the VFD parameters to see how this would be done.


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## markba633csi (Jan 12, 2019)

If your converter is a Phase Perfect electronic unit those are efficient and reliable- I wouldn't be in a hurry to get rid of it as long as it works
Or is this a simple box with capacitors? Those are the boxes that give only a portion of the motor HP (usually 2/3)
mark
ps can you post a picture of it?


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