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Author Topic: Power Supply(s)  (Read 6147 times)

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Re: Power Supply(s)
« Reply #10 on: August 23, 2008, 01:58:42 AM »
Hmmmm. Jethro Tull....Aqualung.
"He bends to pick a dogend"
Is that what I think it is ?
Poor old sod.

Offline Hood

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Re: Power Supply(s)
« Reply #11 on: August 23, 2008, 02:59:59 AM »
Ha ha


RC
 the only thing I would be worried about is that because its not for you the new owner may take it upon himself to crank up the velocity thus increasing the voltage ::o

Hood
Re: Power Supply(s)
« Reply #12 on: August 23, 2008, 06:50:16 AM »
I see what you mean Hood. I'll just make sure that he is well aware.
Thanks,
RC

Offline Hood

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Re: Power Supply(s)
« Reply #13 on: August 23, 2008, 08:31:56 AM »
Hmmmm. Jethro Tull....Aqualung.
"He bends to pick a dogend"
Is that what I think it is ?
Poor old sod.

You are showing your age now ;D

Hood
Re: Power Supply(s)
« Reply #14 on: August 23, 2008, 01:10:54 PM »
I am pretty sure in a discussion I had with Maurice at Gecko a few years ago he mentioned there was no problemĀ  running dc brush type servos at 50% or so higher voltage than the motor rating, something to do with the way the amplifiers work , I know a couple of machines I have worked on in the past (mold handling equip) have had 90vdc motors working with 170+- vdc power supplies.

I know the old bridgeport I am working with came fitted with Reliant 90vdc motors and the original power supply is 177vdc.
I know very little about dc servos and power supplys beyond the basic wiring , just passing along past exp
Re: Power Supply(s)
« Reply #15 on: August 23, 2008, 01:22:41 PM »
RT,
This is what I was referring to...from the gecko manual.
Thanks,
RC
Re: Power Supply(s)
« Reply #16 on: August 23, 2008, 07:40:54 PM »
I am pretty sure in a discussion I had with Maurice at Gecko a few years ago he mentioned there was no problem  running dc brush type servos at 50% or so higher voltage than the motor rating, something to do with the way the amplifiers work , I know a couple of machines I have worked on in the past (mold handling equip) have had 90vdc motors working with 170+- vdc power supplies.

I know the old bridgeport I am working with came fitted with Reliant 90vdc motors and the original power supply is 177vdc.
I know very little about dc servos and power supplys beyond the basic wiring , just passing along past exp

That seems like a bad idea to me.  With servos, you *want* to be able to run high current briefly, to deal with load changes and accelerations.  But, Geckos only have a single current limit adjustment, so it will be active all the time.  If you set it to the motors rated current, them you won't be able to get the peak torque to handle transients.  If you set it for a reasonable peak current, then if you stall the motors, you'll likely exceed their voltage rating.  Mariss indicated to me that the proper thing to do is generally to leave the current limit all the way up, and just use a power supply that is at, or only slightly above, the motors rating.

Regards,
Ray L.
Regards,
Ray L.