I just called Reliance about the cost for the braking resistor. I nearly fainted when I heard a number over $300!!! This thing is a little more than the resistor, there is also the control logic that gets it into the circuit when the DC bus voltage goes up. I understand that some drives have the logic in the drive, and the resistor is the only external part. But looking around I still see this as a really high $ item. Wow!!! My drive cost me $80... it's used, of course, and there's no way I'll stumble across a specialized accessory like that. Still hard to swallow the price!
On 4/8/2006 at 7:19 PM davedamouth wrote:
--- In emcoV10lathe@..., Richard Kleinhenz <richk@...> wrote:
Are you using what's referred to as a 'snubber resistor' in my VFD
manual? Had you tried without that and found you needed it, or is it
something that is just generally recommended and should always be used?
Not sure on the terminology your manual is using. All but the very
cheapest vfd's can usually use a braking resistor. It's a large
resistor that will attach to an extra set of terminals. Allows for
much faster deceleration than just the drive transistors. At 30 rpm,
a 1/2 second braking ramp will stop the spindle in 1/4 revolution.
I use them wherever possible. If something is going wrong, I want the
spindle to stop quickly. Even changing the work in and out of the
chuck goes quicker when you don't need to wait for it to stop.
--
Regards,
Rich
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Richard Kleinhenz
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