The Shop > Tools
phase convertor
Andrew Wildman:
Dave, if you don't mind me asking, how many quid was the transformer?
DavidA:
Andrew,
No problem. It was £225 + £15 carriage.
Quite expensive for a transformer, But now I have it it should be very versatile.
I did notice something about it that I didn't expect. But I'll come back on that when I have done a few measurements.
Dave.
DavidA:
Thomas,
Andrew wrote,
.. Also will require 500v caps which you may find hgarder to get hold of...
This is true. But you can always put two or more capacitors in series and this will increase the working voltage. But it will reduce the capacitance.
So two 250 volt 10 MicroFarad capacitors in series will give you a working voltage of 500 Volt. But an overall capacitance of only 5 Microfarad.
It means more capacitors are needed, but it does work.
Dave.
John Rudd:
And.....dont forget to fit bleeder resistors across them all..... :zap:
Id like to think I can sell you something else of use to you....... :lol:
More seriously, caps exploding isnt funny, Ive had it happen to me, apart from the mess ( of the cap that is.... ) my nerves arent up to it anymore..... ( runs and hides ....)
Id sure like to hear when its finished and how it performs....
What rating are you aiming for Dave?
DavidA:
Joun,
Don't worry, I wont forget the resisters on my set up.
The transformer is a 4 KWatt model.
I'll probably aim at a rating of 1.5 KWatt (to match your motor if I use it as an idler), otherwise it will be rated to the largest motor I have. That would be my Denford lathe at 1.2 KWatt.
With the 240 to 415 Volt transformer I could just use the Steinmetz capacitor set up to derive the artificial phase and leave it at that. But using an idler (Ok, I know it really should be about 2.5 KWatt, but it is only on a low duty) I hope to get a better start up. The chuck is quite heavy.
Anyway we will see.
The motor on my Emco milling attachment is less than 1 KWatt. I have a big drilling machine but the motor on that is only 0,5 KWatt.
So it should all work.
I need to find my AVO and take measurements. Then do some calculating.
Maybe need to build a switched bank of capacitors.
Dave.
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