SLO-SYN SS2000D3 AND SS2000D6 Packaged Chopper Drives PDF Installation Instructions

MOTOR PERFORMANCE
All stepper motors exhibit instability at their natural frequency and harmonics of that frequency. Typically, this instability occurs at speeds between 50 and 500 full steps per second and, depending on the dynamic motor load parameters, cause excessive velocity modulation or improper positioning. This type of instability is represented by the open area at the low end of each Torque vs. Speed curve. There are also other instabilities that cause a loss of torque at stepping rates outside the range of natural resonance frequencies. One such instability is broadly defined as mid-range instability. Usually, the damping of the system and acceleration/ deceleration through the resonance areas aid in reducing instability to a level that provides smooth shaft velocity and accurate positioning. If instability does cause unacceptable performance under actual operating conditions, use the following techniques to reduce velocity modulation.

Avoid constant speed operation at the motors unstable frequencies. Select a base speed above the motors resonant frequencies and adjust acceleration and deceleration to move the motor through unstable regions quickly. The motor winding current can be reduced as discussed in ection 4.5. Lowering the current reduces torque proportionally. The reduced energy delivered to the motor can decrease velocity modulation.
Use the half-step mode of operation or use microstepping to provide smoother operation and reduce the effects of mid range instability. Microstepping reduces the shaft speed for a given pulse input rate.

In General
Check all installation wiring carefully for wiring errors or poor connections. Check to see that the proper voltage levels are being supplied to the unit. Be sure that the “POWER” LED lights when AC power is applied. Be sure that the motor is a correct model for use with this unit. Disconnect the control interface connector. With the motor connected and AC power applied to the drive, push the front panel “Test” switch. The motor should rotate at about 1/2 rev. per second. If it does rotate, the motor, drive, AC input and associated wiring are probably OK. The problem is most likely in either the pulse source or control wiring to the drive.

If the motor does not turn, there is a problem with the drive, motor, AC input or associated wiring. Specifically IF MOTOR DIRECTION (CW, CCW) IS REVERSED, Check For: Reversed connections to the Motor Connector. Reversing the phase A or the phase B connections reverses the direction of motor rotation. IF THE MOTOR MOTION IS ERRATIC, Check For: Supply voltage out of tolerance. Proper motion parameters (low speed, acceleration/deceleration, jog speed, home speed and feed rate). Set parameters on controller supplying pulse input to drive. IF TORQUE IS LOW, Check For: All Windings Off active or Reduced Current active. Improper supply voltage.

ELECTRICAL INTERFERENCE PROBLEMS
Electrical interference problems are common with today’s computer-based controls. Such problems are often difficult to diagnose and cure. If such a problem occurs with your system, it is recommended that the following checks be made to locate the cause of the problem.
1. Check the quality of the AC line voltage using an oscilloscope and a line monitor. If line voltage problems exist, use appropriate line conditioning,
such as line filters or isolation transformers.
2. Be certain all recommended wiring practices are followed for location, grounding, wiring and relay suppression (see Section 3.1).
3. Double-check the grounding connections to be sure they are good electrical connections and as short and direct as possible.
4. Try operating the drive with all suspected noise sources switched off. If the drive functions properly, switch the noise sources on again, one at a time, and try to isolate the one(s) causing the interference problems. When a noise source is located, try rerouting wiring, suppressing relays or other measures to eliminate the problem.

Download SLO-SYN SS2000D3 AND SS2000D6 Packaged Drives PDF Installation Instructions