Re: [CAD_CAM_EDM_DRO] GeckoDrive: seeking practical advice about the Big Capacitor !

If you are drawing 5A from the 15000uF cap, and you are charging it with a
full wave bridge, then the capacitor voltage should be dropping about 2.8V
between half cycles of the AC line. You can verify that by measuring with
the AC range on your voltmeter, which should indicate about pi/8sqrt(2) of
the peak-to-peak value, or about .77V.

A bigger cap would reduce the ripple, but the 2.8V drop doesn't seem big
enough to be worth reducing.

What do you mean "This design does not allow greater than 36 Volt?" Are you
limited by your transformer? If that's the limitation, you could build a
voltage doubler and get about 72V.

Cheers,
- Jan

----- Original Message -----
From: "Hans Wedemeyer" <xyz@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, March 16, 2003 3:24 PM
Subject: [CAD_CAM_EDM_DRO] GeckoDrive: seeking practical advice about the
Big Capacitor !


> I now have a Gecko Drive (G201) driving a PacSci motor which is rated at 5
Amps/Phase in a parallel connection.
>
> The Gecko is set to 5 Amp (using a 120K set R) Supply Voltage is regulated
36 Volts at 8 Amps. At the Gecko ( 6 inches from it)
> there is a 15,000uF 50 Volt Cap.
>
> Under no load conditions the motor can reach the speed required, but under
load it reaches a point where
> it makes a horrible sounds and stops rotating.
>
> Under normal circumstances if I could increase the Voltage to (say 50-60V)
I feel sure the motor would continue to rotate.
>
> This design does not allow greater than 36 Volt.
>
> My Question:- I have space for a 56,000uF 50 Volt Cap. . Does anyone have
experience of the result of increasing the Cap. Value by almost 4X , would
it help solve the problem or is it a waste of time
> ?
>
> Best Regards
> Hans W