19 Feb
2010
19 Feb
'10
8:20 p.m.
On the Siemens drives also used in the H89 and H17,
there is an inductor
in series with the +12 to the spindle motor. It's a hash choke that keeps
the motor noise from going back into the +12 rail. When the grease in
the spindle motor gets old and sticky, the motor draws way too much current
at startup (if it ever does start spinning) and toasts this inductor.
If this is the Siemens drive used in the Z90, I have the schematics here
(io the Z90 hardware manuals). I can't see an 'L5' at all, but the drive
I have has a separate motor control PCB with a series choke (but a 10uH
one) in the supply line. It's easily posible that later drives put
everything on one PCB (as Tandon did).
-tony