Horsepower rating
Posted by
tommy marantz
on 2000-03-14 14:58:01 UTC
De lurking for a bit,
Many commercial stepper motors can produce suprising peak (but real) HP. My
old Sigma catalog shows peak hp at about 1.2 @ 10,000 steps per sec. for
some 4.2"d x 8"l models. This was using a 90V drive.
The purpose of the high voltage drive is to overcome the motors inductance
so it will step (run) fast. The motor is not absobing the full 90V at 13A
per phase. The average phase current is lower since it spends time ramping
up and ramping down.
A good drive will get the current up to full rating way before the next
step, so higher voltage is better in this sense. At full current, you get
full torque. spend time ramping current, you get less torque.
Get high torques at higher speed, you get higher HP.
The HP of course does not come for free and motors are not 100% efficient,
special steppers have claimed 80% efficiency vs standard types that get 40%.
Ideally 1HP = 750 Watts.
Hope this helps
Tom
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Many commercial stepper motors can produce suprising peak (but real) HP. My
old Sigma catalog shows peak hp at about 1.2 @ 10,000 steps per sec. for
some 4.2"d x 8"l models. This was using a 90V drive.
The purpose of the high voltage drive is to overcome the motors inductance
so it will step (run) fast. The motor is not absobing the full 90V at 13A
per phase. The average phase current is lower since it spends time ramping
up and ramping down.
A good drive will get the current up to full rating way before the next
step, so higher voltage is better in this sense. At full current, you get
full torque. spend time ramping current, you get less torque.
Get high torques at higher speed, you get higher HP.
The HP of course does not come for free and motors are not 100% efficient,
special steppers have claimed 80% efficiency vs standard types that get 40%.
Ideally 1HP = 750 Watts.
Hope this helps
Tom
>I have a hard time seeing 90 V @13.2 A per phase (x2) = 3.19 hp.______________________________________________________
>The motor is smaller than a 3/4 hp induction or synchronous >motor...could
>the above numbers be 'peak hp', like
>vacuum cleaners specify?
>Something doesn't add up for me.
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