"Jim Lesurf" wrote in message
...
In article
, Roger
Thorpe
wrote:
William Sommerwerck wrote:
Many turntables have a line resistor. It "does
something" (that I
don't understand) to improve speed stability. Or
torque. Or something.
It's not to reduce the line voltage.


It's a while since I looked, and I could be wrong but:
The Rega planar
motor is a pair of multi pole two phase synchronous
pancake motors
sandwiched together with the poles interleaved. The
resistor and
capacitor are there to change the phase (lag or lead?) of
one motor so
that the assemlby turns in the right direction when it is
started.

That chimes with my understanding, based purely on having
had to 'fix' a
similar problem with a friend's Rega a few years ago.
Haven't commented
previously as I don't know the full details.

Now, since you have now commented, you *do* have the full
details, presumably?

I just replaced the burnt out
resistor with one rated at a higher power. And have since
forgotten the
value.

Oh...maybe not

Must admit I was less than impressed with the circuit at
the time. From
this thread it does look like this resistor is prone to
burning. Although
perhaps that is made worse by the risk of the motor being
stalled or
loaded.

Perhaps? Certainly, surely?

Is it really likely, do you think, that the manufacturer
would continue to fit an inappropriate resistor for so long?
It's not like resistor power rating is complicated or
arcane. Cost difference can't be that significant, and
there's no shortage of space.

It would be interesting to know how the winding resistance
compares with the impedance of an up-to-speed motor. If the
difference is great enough, it could be that all those
burned-out resistors are a result of stalled motors or
increased drag, or even the fitting of heavy platters. It's
also possible that every burned-out resistor has saved a
motor winding, in which case a higher-rated resistor would
be a liability.

Ian