IM483H/IM805H Rev. R032206
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IM483H/IM805H Rev. R032206
S e c t i o n 5
P o w e r S u p p l y R e q u i r e m e n t s
S e c t i o n O v e r v i e w
This section covers the power supply requirements of the IM483H/IM805H.
Precise wiring and connection details are to be found in Section 7:
Interfacing
to the IM483H/IM805H
. The following is covered by this section:
n
Selecting a Power Supply.
n
Recommended Wiring.
n
AC Line Filtering.
S e l e c t i n g a P o w e r S u p p l y
S e l e c t i n g a M o t o r S u p p l y ( + V )
Proper selection of a power supply to be used in a motion system is as im-
portant as selecting the drive itself. When choosing a power supply for a step-
ping motor driver, there are several performance issues that must be addressed.
An undersized power supply can lead to poor performance and possibly even
damage to your drive.
T h e P o w e r S u p p l y - M o t o r R e l a t i o n s h i p
Motor windings can basically be viewed as inductors. Winding resistance and
inductance result in an L/R time constant that resists the change in current.
To effectively manipulate the rate of charge, the voltage applied is increased.
When traveling at high speeds, there is less time between steps to reach current.
The point where the rate of commutation does not allow the driver to reach full
current is referred to as voltage mode. Ideally you want to be in current mode,
which is when the drive is achieving the desired current between steps. Simply
stated, a higher voltage will decrease the time it takes to charge the coil and,
therefore, will allow for higher torque at higher speeds.
Another characteristic of all motors is back EMF. Back EMF is a source of
current that can push the output of a power supply beyond the maximum oper-
ating voltage of the driver. As a result, damage to the stepper driver could occur
over a period of time.
T h e P o w e r S u p p l y - D r i v e r R e l a t i o n s h i p
The IM483H/IM805H is very current efficient as far as the power supply is
concerned. Once the motor has charged one or both windings of the motor, all
the power supply has to do is replace losses in the system. The charged winding
acts as an energy storage in that the current will recirculate within the bridge
and in and out of each phase reservoir. This results in a less than expected cur-
rent draw on the supply.
