The Shop > Tools
phase convertor
DMIOM:
--- Quote from: DavidA on November 01, 2015, 01:40:57 PM ---A progress report; sort of.
I have been waiting for the arrival of a capacitance meter to find out what the value of the capacitors I have actually is as against what it says on the can.
The calculated value required is 4.16 MFD.
My nominal 7.5 MFD unit measured at 6.7 MFD. Near enough for a test. I'm expecting a high voltage because of this.
...........
--- End quote ---
Not surprised if your caps are Mega Farads.... :scratch:
Bluechip:
--- Quote from: DMIOM on November 01, 2015, 06:44:34 PM ---
Not surprised if your caps are Mega Farads.... :scratch:
--- End quote ---
:lol: :lol: :lol:
Dave
DavidA:
DMIOM,
...Not surprised if your caps are Mega Farads....
If you go to the following site..
https://en.wikipedia.org/wiki/MFD
and look at the third item in the section on science, technology and medicine, you will find that MFD is the old abbreviation for MicroFarad; which was the way I intended it to be understood. Old habits die hard.
I understand that humble pie is best served with a chilli sauce.
I didn't use the Mu character as I don't know how to get it.
Anyway, onwards.
It dawned on me last night that the best way to go would be to first connect the motor directly to the three phase supply, by-passing the contacter.
Upon doing this the milling attachment whirred into life. A success.
The artificial phase measured 459 Volt. I did predict it would be high.
So, just the contacter to sort out and a new capacitor to get (from RS) and then I can get on to trying the lathe electrics.
If I could only find my clamp meter I could also check a few currents.
Dave.
Bluechip:
DavidA:
I have some Ducati motor start caps. marked eg. 12 MFD and they aren't all that old. So, the terminology is not quite obsolete .
I also had some ancient LEMCO & Dubilier silvered mica and waxed paper caps. marked uuF for picofarads and mmF for microfarads.
Slung 'em out some years ago together with anything with 'Hunts' on it ... :bang:
Dave
DavidA:
I posted on another thread that today I had a go at getting the Denford to run.
As I have mentioned, I bought this lathe from the company I worked for; but hadn't seen it run for a while.
I first got the EMCO milling attachment running using my capacitor type three phase system. So far so good.
When I connected the lathe to the same system it knocked out the RCD. We are now up to date.
Today I had a look inside the control panel. Lots of unexpected electrics.
It has a DC injection brake system fitted. And I don't know anything about them.
But I don't think I really need to use it. So I will by pass it ; at least for now.
I connected the three phase supply direct to the motor. (after removing the original connections) and tried it. A loud(ish) hum and signs of the motor trying to turn.
Turned it off again and reasoned that this thing hadn't been run for a while and maybe best to disconnect the variable speed belt and just run the motor on it's own; no load.
Try again. Motor runs slowly with a distinct two - phase growl.
Not a problem as I know that the calculated capacitance for the 2.2 Amp motor is around 16 MFD; and I only had 7 MFD in circuit.
Time to order up those capacitors I referred to earlier.
Then also time to set up the idler motor. That should help it start easier.
Dave.
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