Vfd info

I just noticed a better pic of the schematic. And now see it does not have any capacitor(s) in the circuit. I do see a choke, L1, so that brown cylinder thing is probably the choke. Whatever DC motor you try to run with this VSD, note that some DC motors have a permanent magnet field and do not need a DC source for the field. In this situation you just supply DC to the armature and it can be fixed or variable voltage for variable speed. And another note, the armature supply is typically of a higher current demand that the field current…Dave.
 
Baldor draws 1.55 amps..1/7 hp...bought from a equipment co..guy said vfd and vsd.same thing..my dumb ass ...so if I replace the small blue rectifier it should hold up to the Baldor but not the bodine..thanks very much for your knowledge..Phil
Leave the bridge rectifier alone. Hook it up and see if it runs first. It should handle 1.7 amps easily. Change out the fuse with a 2 amp and don't look back. Old electronics like this are generally oversized a bit for venturous guys like us to piddle with. If it does blow, then put in a larger BRF in. Otherwise, plug it in and giver her a try! What's the worse it's going to do? Give off some magic smoke? This is how you learn about old school electronics.
 
Ken what does one need for a x axis power feed? 1/8 horse? 1/6?
I'm afraid lordbeezer's box isn't going to cut it with either of the motors he has.
Mark
If you use one of them sub fractional HP gear motors, say 1/12 or 1/8 HP, probably work fine. I'd rather spend the extra money and get one of those Severo-feed hook ups to use and not mess with anything else in my opinion. It really doesn't take much torque to turn the crank on the mill to feed a end mill thru a cut. Set up a beam type torque wrench that reads in in/lbs, attach on the nut on the feed screw and turn it to read the torque while feeding it thru a cut. Then work off of that for sizing a gear motor.
 
Agree totally with Ken as above. Try a 2 amp fuse and don't look back. Baldor OK Bodine NO
The speed regulation will not be real good and the low speed torque will drop off somewhat
Also be careful since the box has no isolation transformer! Make sure you ground the box, and the motor.
Mark
ps Lear Siegler isn't that the same Lear that made Learjets?
 
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Ran the Baldor for awhile with the vSd..nothing got warm..ran 2.25hp 10amp 90v pm motor for about 15 minutes.different speeds.did ok with no load..very smooth. Thanks everyone for your helping me get a little knowledge on this stuff..going to pick up big press from guy that sold me the wanna be vfd..
 
Until you put a load on the motor, you will not know if it will smoke or not.:blowup:
 
Heard that...probably gonna use the Baldor gear motor on mill power feed..just had to try the 10 amp motor..thanks
 
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