Re: Running a 3 speed motor from a converter
- From: "Dad" <simon.cochran1@xxxxxxxxxxxx>
- Date: Mon, 24 Jul 2006 22:04:26 GMT
Hi Dave.
Cant remember the exact formulae for current calcs, but that aside a
few things spring to mind. Obviously it would appear on the face of it that
your converter dose not have a sufficently high current output to run the
motor at high speed, while you may be able to fiddle with it to some extent
to force it to run, you cant get round ohms law which basically means that
while you are under running the motor the windings will be generating more
heat as the voltage drops, this is because the heat generated =I R squared.
Basically what happens is as the voltage drops the current increases, and
current is the heat generator. What this means is shorter service life of
both motor and converter.
Next thought is that the converter is really only suited to small ish loads,
and a more suitable unit would be a static converter, which is basically a
toroidal transformer and capacitor bank, which gives much closer to a true
three phase supply {even though far from perfect}and it dose not suffer from
voltage wander in the same way as the transwave unit, as this uses the other
motor as an inductive load and so is tuned in this manner to a specific
current and phase angle, once you go outside the current range the phade
angle dies fairly quickly. What this means is to some extent they stop
generating the phase angle and instead the generate 3 phases with less
angular differance, or more simply all three phases become more or less the
same.
Hope this helps
"Dave" <nomail@xxxxxxxxxxxxxxx> wrote in message
news:4ikgiiF47g6lU1@xxxxxxxxxxxxxxxxx
I'm trying to get a Holbrook C10 running on a 3.7kW Transwave converter;
has anyone managed to get multi speed motors working OK on a converter?
The C10 has a 3 speed (2860, 1430 and 925 RPM) 2HP motor that drives a 2
speed clutch/gearbox assy; with backgear this gives 12 spindle speeds.
Without a pilot motor it's difficult to find a switch setting on the
converter that will run the motor at sensible voltages at all 3 speeds and
when the fast clutch is engaged at 2860 the motor slows significantly and
won't come back up to speed - after a few seconds the motor protection
trips.
With a pilot motor (5HP 2800RPM) the voltages are more sensible at the 3
motor speeds but the lathe still won't run at the highest spindle speed
(2000 RPM).
These tests were done without a chuck mounted so the problem may occur at
other speeds with the extra inertia to be overcome.
Any ideas?
Dave
.
- Follow-Ups:
- Re: Running a 3 speed motor from a converter
- From: Dave
- Re: Running a 3 speed motor from a converter
- References:
- Running a 3 speed motor from a converter
- From: Dave
- Running a 3 speed motor from a converter
- Prev by Date: Re: Warco BH600 arrived - not working!
- Next by Date: What to look for in a pillar drill
- Previous by thread: Re: Running a 3 speed motor from a converter
- Next by thread: Re: Running a 3 speed motor from a converter
- Index(es):
Relevant Pages
|
Loading
