On Tue, 24 Jun 2008 10:42:34 +0200, NoSp <NoSp@[EMAIL PROTECTED]
> wrote:
>Rich Webb wrote:
>> On Mon, 23 Jun 2008 14:55:43 +0200, NoSp <NoSp@[EMAIL PROTECTED]
> wrote:
>
>>> Or should I (in addition to this) add some capacitors across the
>>> +12V/GND and +5V/GND lines close to each relay as well?
>>
>> The power supply will be on the upstream side of the relays and won't
>> help to smooth the effects of any contact bounce on the load side of
the
>> relays. But, there's probably enough capacitance on the drive's power
>> rails already.
>
>Yes, that makes sense.
>Should I connect something like a caramic capacitor across each of the
>relay's switch connections? Which capacitance values are we talking?
Just swagging this: The 12 V shouldn't care; the drive motor isn't spun
until after the drive electronics start up. On the 5 V rail, it looks
like a typical modern drive initially pulls about 300 mA. Hand-waving a
power interrupt time during contact bounce at around 1 ms, to hold the
droop on 5 V to < 10% would require about 600 uF.
--
Rich Webb Norfolk, VA
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