In message , The Natural Philosopher
writes
On 08/02/14 09:37, Andrew Gabriel wrote:
In article ,
"harryagain" writes:

wrote in message
...
On Thursday, 10 September 2009 11:45:08 UTC+1, robert wrote:
Have acquired an old pedestal drill with a
British Houston Thompson single phase 1/4hp motor
marked KF TD3205 type BS 2408

The motor start capacitor needs replacing but it has no visible markings
on it due to several paint coatings !

With capacitor removed the motor will run with a hand start and I can
hear what I assume is a centrifugal switch clicking on spin up and spin
down.

Any advice on what size capacitor to buy and try ?

I have one of these motors and it does not appear to have a capacitor on
it . It starts but dips the lights in my workshop as it is pulling a few
amps on
start up is the capacitor internally mounted?

There are various designs, some with some with a capacitor, some without.
Induction motors inherently have poor starting torque.

The ones with a capacitor are marginally better and hence will start against
a amall load/run up to speed quicker.

Just wondering if the OP knows for sure it's a capacitor-start
motor, rather than a capacitor-run motor? The second also gives
a higher running torque, but uses higher grade capacitors.

He did say something about a centrifugal switch, which suggests start
alone..

Umm.. A centrifugal switch could also indicate a simple split phase
motor: where the LR ratio of a secondary winding gives a small phase
change and does not require a capacitor.

Long while since I actually anything about this:-)



--
Tim Lamb