On Thu, 31 Dec 2009 04:39:47 -0800 (PST) Andy
wrote in Message id:
:

I have a small single phase blower motor which requires a capacitor
for running (not starting). The motor nameplate says that I need 7.5
microfarads. I have a pair of 5 microfarad caps in the shop. I
hooked up the motor with just a single 5 uF and it didn't start. Then
I put the pair in parallel and the motor did start. If I use 10 uF I
will draw more current into the directional winding of the motor. So
my question is, how closely are these caps sized? Is the difference
between 7.5 and 10 uF enough to do damage?

Can't answer your question, but Digikey carries 7.5uF AC run caps. For $10
or so, better safe than sorry I always say.