Moons' MSSTAC6 User Manual page 27

MSSTAC6 Step Motor Drive User Manual
The STAC6 drives work best with the recommended specially matched motors. To configure the drive for
one of these motors, select it from the drop down Standard Motor list. The Rated Current for the selected
motor will appear in the Motor Specs section. If an application is particularly heat sensitive and there is more
torque available than needed, motor heating may be reduced by lowering the current. If a duty cycle is short,
giving the motor time to cool down between moves, the current may be set higher than rated to increase the
torque. However, motors operated above their rated current will not run as smoothly, and, if used
continuously, could overheat.
Reducing the Idle Current reduces motor heating by lowering the current when the motor is at rest. In
most cases, the default value of 50% works well. Motor heating may be further reduced by lowering the Idle
Current percentage even more.
The Idle Current Delay is the amount of time between when the motor stops and the reduction of the
current. It is recommended to allow a little time for the motor to settle out before the current is reduced.
Load Inertia
The anti-resonance feature is most effective if the load inertia is set precisely. If this is a known value,
the first option circle should be clicked, the inertia entered, and units of measurement selected. If the exact
inertia is not known, the second option circle should be selected and an approximate load to motor inertia
ratio entered. This number can be adjusted as needed.
Defining a Motor not in the Recommended List
The list of recommended motors has been created to increase the probability of an application being
successfully and quickly implemented. The chance of this is highest when a high quality motor is used
whose torque, rotor inertia and harmonic waveform content are precisely known. These suggested motors
come with shielded cables to reduce electrical emissions and enhance safety, and with prewired mating
connectors which further reduce the risk of error.
However, if a custom motor is used, detailed information from the manufacturer will be needed. This
includes electrical specifications (holding torque, rated current and rotor inertia) as well as a wiring diagram.
The motor must also be constructed from high quality magnetic materials that are suitable for operation with
the 160 volt busses used on the MSSTAC6.
To define a Custom Motor, that circle should be checked and the Define Custom Motor button clicked. In
the Add New Motor dialog box, current, torque and inertia values are entered. For the smoothest motion, the
harmonic distortion gain and phase should be entered. This may need to be determined by running the
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