On 12/3/01 10:42 PM, Dan Evans at n9rla@yahoo.com wrote:
>Before we start climbing, or I should say, he starts climbing [I never could
>stand to climb!!], is there anything else we should check? Several folks
>have mentioned the starter cap, is there a way to check these? I don't have
>a capacity check on my meter.
Find a 100v, 150 uF cap. Disconnect leads 4 and 8 from the control box
and put them across this cap. If the rotator turns, it is the motor
capacitor. It is a frequent failure point for HAM rotators. Fortunately,
it is also easy to fix.
One thing you might consider is to mount the capacitor up near the
rotator instead of in the control box. You can then use the two extra
conductors for the brake. (Parallel conductors 1 and 2)
While you can just just about any electrolytic capacitor to do the test
above, get a proper replacement -- an un-polarized capacitor of the
proper value, and current-handling capability. Ordinary electrolytics
aren't really designed to carry the currents in this service and will
heat up considerably.
BTW, technically, it isn't a "starter" cap. It doesn't just start the
motor, but it supplies power to the other motor winding with a shifted
phase. It greatly increases the motor torque. Even an unloaded rotator
won't turn if the cap fails, and turn very weakly if encouraged.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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