Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: piccyman on April 20, 2014, 02:02:50 PM

Title: Is this a suitable power supply
Post by: piccyman on April 20, 2014, 02:02:50 PM

Hi,

I have bought a http://www.cnc4you.co.uk/index.php?route=product/product&product_id=280 48V 12A CNC Power Supply

Do you think that this power supply is too higher voltage for the kit i have, 3 nema 23's and 1 nema 17

I have attached the spec on the 3 nema 23 motors and the motor driver


Thank you

Title: Is this a suitable power supply
Post by: JohnHaine on April 20, 2014, 06:15:42 PM

It's the current that fries the motors not the voltage.  Do the drivers have provision to set the motor current?  Can you provide a link to the driver details?


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Title: Re: Is this a suitable power supply
Post by: HimyKabibble on April 20, 2014, 09:34:18 PM

48V is just about perfect for the NEMA23s.  Voltage should be 32 * SQRT(MotorInductance), which, in this case comes out to 50V.

Regards,
Ray L.

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 03:00:35 AM

There is a pot on board that will adjust the current from .5A to 4.5A http://www.mib-instruments.com/servlet/the-3453/TB6600-Stepper-Motor-Driver/Detail

Thank you

Title: Re: Is this a suitable power supply
Post by: JohnHaine on April 21, 2014, 04:43:32 AM

That looks like a useful driver.  Set the current pot to the rated current for your motors before powering up.

It goes without saying I guess, but mount the board in the vertical plane so that air can convect past the heatsink.

Title: Re: Is this a suitable power supply
Post by: stirling on April 21, 2014, 05:43:22 AM

The page you linked to for the driver appears to give a range of 12 to 36V. The datasheet for the TB6600HG's gives an absolute max rating of 42V so the 36V seems appropriate. There are several warnings on the data sheet about the consequences of going over this absolute max of 42V - most of which seem to involve some form of mayhem  ;).

Ian

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 05:48:03 AM

i saw that, except the Toshba spec is 50v for the chip and in the documentation that came with the drivers states 50v

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 06:19:40 AM

http://www.toshiba-components.com/docs/linear/TB6600HG_en_datasheet.pdf  this data sheet?

Do you think i should find a lower voltage supply?  like 36v

Title: Re: Is this a suitable power supply
Post by: Picengraver on April 21, 2014, 06:41:46 AM

"The power supply voltage of 42 V and the output current of 4.5 A are the maximum values of operating range."

This quote is from the data sheet you referenced.  The 50V is not an operating voltage.  Stay safe, use 36v or 24v.
Regards,
John Champlain

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 06:43:05 AM

ok, thank you

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 06:54:55 AM

Can anyone suggest a good one

I am looking at possibly buying this one

http://www.amazon.co.uk/Regulated-Switch-Power-Supply-Converter/dp/B008DFCJYO/ref=sr_1_13?s=electronics&ie=UTF8&qid=1398076960&sr=1-13&keywords=24V+15A

Title: Re: Is this a suitable power supply
Post by: stirling on April 21, 2014, 07:06:39 AM

Personally I'd be thinking closer to the 36V rather than 24V. Also 15A is waaaaaaay over what you'll need for the motor specs you've posted.

Title: Re: Is this a suitable power supply
Post by: piccyman on April 21, 2014, 08:26:40 AM

is this better?

http://www.cnc4you.co.uk/index.php?route=product/product&path=20_65&product_id=278

Title: Is this a suitable power supply
Post by: JohnHaine on April 21, 2014, 03:54:37 PM

That's the one I use for my Denford Novamill conversion.  Works well.


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