Projecta IM2000 Instructions d'exploitation télécharger pdf (Page 20)

Section 5

Power Supply Requirements

Section Overview

This section covers the power supply requirements of the IM483. Precise wiring

and connection details are to be found in Section 7: Interfacing and Controlling the

IM483. The following is covered by this section:

 Selecting a Power Supply.

 Recommended Wiring.

 AC Line Filtering.

Selecting a Power Supply

Selecting a Motor Supply (+V)

Proper selection of a power supply to be used in a motion system is as

important as selecting the drive itself. When choosing a power supply for a

stepping 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.

The Power Supply - Motor Relationship

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

operating voltage of the driver. As a result, damage to the stepper driver could

occur over a period of time.

The Power Supply - Driver Relationship

The IM483 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

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Projecta IM2000 Instructions d'exploitation Page 20