I just bought a Snap AMP after reading through the specs. Sounds like a very capable controller. I have been searching for appropriate servo motors. I really don't need more than about 500 watts for my application.
Here is a motor that I found, but wanted your input to see if you think that it would work well. The one issue I see is that it says 220 VAC as the power requirement. This is probably the spec for the driver, not the motor. Do you think this one would work? If not would you be able to recommend another supplier?
Thanks,
Scott
Group: DynoMotion
Message: 11150
From: Tom Kerekes
Date: 3/3/2015
Subject: Re: Snap Amp
Hi Scott,
That motor should work except as you mention it is a fairly high voltage motor for SnapAmp. It has a back emf of ~32V per 1K RPM. This means that at 2000RPM the motor will require more than 64V to generate any torque at all. So with SnapAmp's Max supply voltage of 80V only ~2000RPM will be usable. A higher current lower voltage motor winding would be more appropriate if you need higher speed.
HTH
Regards
TK
Group: DynoMotion
Message: 11154
From: cnc_machines
Date: 3/3/2015
Subject: Re: Snap Amp
Tom,
Thanks, I missed that on the spec sheet. Do you have a favorite motor manufacturer, or one that you would recommend that works well for the SnapAmp? I would like to have at least 3,000 usable RPM.
Scott
Group: DynoMotion
Message: 11155
From: Tom Kerekes
Date: 3/3/2015
Subject: Re: Snap Amp
Hi Scott,
No sorry I don't. If any one else does please post.
Regards
TK
Group: DynoMotion
Message: 1176
From: morgtod
Date: 5/25/2011
Subject: Snap Amp
To use the snap amp at the higher amperage values on a single brushed servo, do the axis0 and axis1 outputs have to be tied together somehow? I have a toolchanger servo on axis0 and Z servo on axis1, they will never be able run at the same time, can axis1 handle 25 amps peak when axis0 is not running? My power supply is putting out 79 volts, is this ok? What is the absolute max voltage?
Todd
Group: DynoMotion
Message: 1177
From: Tom Kerekes
Date: 5/25/2011
Subject: Re: Snap Amp
Hi Todd,
No DO NOT tie any outputs together. I think you should be ok. SnapAmp has 4 full bridge drivers. Two on each "side". As long as the total current on each "side" is always less than 12.5A cont and 25A peak it should be ok.
All the components are rated for at least 100V, but we spec the board for 80V to allow for spikes and such, so you should be ok if 79V is the max rather than the average.
Regards
TK
Group: DynoMotion
Message: 4187
From: bradodarb
Date: 3/6/2012
Subject: Snap Amp
Hello Tom,
I was looking at a servo application using some 800w servos. With a SnapAmp powering the servo on a 100lb-150lb carriage will I need a braking resistor, or can it brake/regen?
-Brad Murry
Group: DynoMotion
Message: 4188
From: TK
Date: 3/6/2012
Subject: Re: Snap Amp
Hi Brad,
Yes SnapAmp has an on board 25W regenerative braking resistor. Peak power dissipation of ~2KW per supply. It can plot the supply voltage in real time to show how the clamping is working.
TK
On Mar 6, 2012, at 8:05 PM, "bradodarb" <bradodarb@...> wrote:
Hello Tom,
I was looking at a servo application using some 800w servos. With a SnapAmp powering the servo on a 100lb-150lb carriage will I need a braking resistor, or can it brake/regen?
-Brad Murry
Group: DynoMotion
Message: 4238
From: Brad Murry
Date: 3/16/2012
Subject: Re: Snap Amp
Hello Tom,
Can an external resistor be employed for high inertia (potentially under-powered) systems?
-Brad Murry
From: DynoMotion@yahoogroups.com [mailto:DynoMotion@yahoogroups.com] On Behalf Of TK Sent: Tuesday, March 06, 2012 4:13 PM To: DynoMotion@yahoogroups.com Subject: Re: [DynoMotion] Snap Amp
Hi Brad,
Yes SnapAmp has an on board 25W regenerative braking resistor. Peak power dissipation of ~2KW per supply. It can plot the supply voltage in real time to show how the clamping is working.
TK
On Mar 6, 2012, at 8:05 PM, "bradodarb" <bradodarb@...> wrote:
Hello Tom,
I was looking at a servo application using some 800w servos. With a SnapAmp powering the servo on a 100lb-150lb carriage will I need a braking resistor, or can it brake/regen?
-Brad Murry
Group: DynoMotion
Message: 4239
From: Tom Kerekes
Date: 3/16/2012
Subject: Re: Snap Amp
Hi Brad,
I'd be suprised if you need more than the on-board 25W resistor (per axis). I know of a system driving 800lb gantrys without a problem.
The power resistor is soldered in and the FPGA logic limits the average power that it will attempt to absorb so increasing the rating wouldn't do any good.
If you really needed to absorb more power you would need to add an external voltage clamp to the power supply or possibly just a huge capacitor. SnapAmp has software programmable voltage clamping level so it could be set a few volts higher than the external clamp so it wouldn't be doing the clamping.
