# Phase Converter - BP Series 1 2 HP



## Bamban (Nov 26, 2014)

When I bought the mill a couple or so months ago it came with a phase converter. The seller said he just used the converter in factory setting, something I never bothered to read in the manual on what that is. Basically been running it with what he had in it.

Have to admit have not done a lot of work with the mill as my learning effort has been on the lathe. I do not know if it is a problem, but the max frequency I can run on the converter is 37 HZ. If I were to go any higher, it faults out and had to crank down and reset. The other thing I noticed even at the 37 HZ setting when I turn on the spindle it spools up real slow.

Questions:

Is that normal performance in that combination?

Or should I RTFI and figure out how to set this box up?

If I were to snag a 2-3 HP VFD, how would you operate the speed control, still use the crank or leave the crank at some setting and control the speed range with the VFD?

TIA


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## JimDawson (Nov 26, 2014)

It sounds like the Full Load Amps (Motor Name Plate Amps) is not set correctly.  VFDs normally are set low out of the box and you have to make some adjustments.  Also it sounds like The Accel Ramp is set too long, normally the factory default is set at 10 seconds.  I have mine set for 2 seconds, and the Decel is set for 2.5 sec

It's time to browse through the manual a bit and get it set up for your machine.

I normally leave my VFD set at 60 Hz, and use the variable speed belt to change speeds.  Sometimes I turn it down for power tapping, reaming and other light operations, rather than put the mill in low range.


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## sdmuleman (Nov 28, 2014)

Read tha manual and make sure that the FLA on the VFD match the motor and that the max frequency setting is where you want it as well. Also make sure the VFD is actually large enough for the motor - may be someone got a 1HP for example and just stuck it on there. 

I would generally recommend setting the VFD for 60Hz and using the variable speed drive to change speeds unless you're doing a lot of changing or for some reason it's difficult to change speeds (worn varidrive, medical issues, whatever) 

Several things to consider when using the VFD:

1) High speeds on the VFD will be rotating the motor faster than designed. Centrifugal force is the square of RPM, so double the speed and you quadruple the forces trying to pull the armature apart. Generally speaking, induction motors are fairly resistant to this, but still worth keeping in mind, especially because it's not impossible that the end result would be the motor exploding. 

2) At low speeds you have much less torque than you'd have with the varidrive. With the varidrive you have a mechanical advantage which you loose with the VFD, and the motor is also less powerful at lower frequencies. For light work it's likely not a problem, but something like a flycutter or large end mill could pretty easily cause problems. 

3) The motor runs less efficiency off it's design frequency, which means more heat. Within about 50-150% (ie 30-90hz) it's likely not going to be a problem, but worth noting. 

4) Lower rpm on the motor means less airflow since the fan is on the motor shaft. Combined with likely high load due to the lower mechanical advantage of the belt drive and lower motor efficiency, this is particularly concerning. 

To me it would depend a lot on what you're doing. If you do a lot of changing speeds within a certain range (say 3000-4200 rpm) then it would make sense to use the VFD since it's quick and easy. I wouldn't want to use it for wide ranges unless you're very careful and only use the extremes rarely. 

I have my boss CNC machines setup to run the full 500-4200 rpm range with the VFD for CNC control, but it's more of a general capability demo than something I'd want to use all the time.


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## Bamban (Dec 1, 2014)

The box is the correct one, 230, 2HP. 

Went into the programming mode, the motor setting was at 1415, I believe the previous owner looked at the 50 HZ RPM. I set it to 1710 the 60 HZ stamped on the motor, and set the FLA to 6.0, it was the 5.0. Set the application from general use to high torque. Ramp is now set at 2.0, and Decel is at 2.5. Left everything else at default. 

I can run 43 HZ max, anything above, it faults for OL code that requires a reset. Press run and crank back the freq to get it back to run.

With the ramp at 2.0 instead of the 30, the default, the motor spools up faster.

Anything else I should be looking for?


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