Rockwell Automation 1336T Master/Slave Parallel AC Drv - Manual (Page 47)

1336 FORCE-5.19 – August, 2000
Chapter
5
Encoderless Operation
Chapter Objectives Chapter 5 provides information specific to encoderless operation of
the Master/Slave version of the 1336 FORCE drive. This chapter
deals with application and parameter requirements that are exclusive
to the Master/Slave drive when operated in the encoderless mode. For
encoderless tuning and troubleshooting information refer to the 1336
FORCE 5.12 User Manual Appendix A.
.
Application Guidelines The Master/Slave encoderless operation has all of the same
limitations as the normal 1336 FORCE encoderless operation. The
maximum velocity bandwidths are lower and continuous operation at
speeds below slip speed (1-2 hz typically) should be avoided (other
than starting). Starting may require minimum speed limits and a faster
acceleration ramp to avoid extended operation in the low speed range.
The following should be taken into consideration when making a
decision on whether to operate in the encoderless mode:
◗ Encoderless is applicable when Speed Regulation requirements
are greater than +/- 1.0% of base speed. Encoderless may be
applicable for regulation between 0.2% and 1.0% with manual
adjustments. Encoder operation is recommended below 0.2%.
◗ Encoderless is applicable when the minimum speed is greater
than 1/40 of base speed (i.e. 45 RPM on a 60 Hz, 4 pole motor).
Encoderless may be applicable down to speeds of 1/60 of base
speed (30 RPM) if high bandwidth responses are not required.
Encoder operation is recommended for speeds < 1/60 of base
speed (30 RPM).
◗ The maximum velocity bandwidth achievable with sensorless is
approximately twice the default bandwidth value. Bandwidths
higher than this may require an encoder because the velocity
ripple may be intolerable or there may be stability problems. The
maximum bandwidth achievable with sensorless is half the
bandwidth achievable with an encoder. Note that the maximum
achievable bandwidths decrease with increasing inertia for both
encoderless and encoder.
◗ The starting torque available is the same with encoderless or
encoder. Available starting torque is at least 150% motor torque
and could be as high as 200% if the inverter can supply the
current.
◗ Minimum (current limit) acceleration and deceleration times are
comparable with encoderless and encoder.
This Topic: Starts on Page:
Application Guidelines 5-1
Parameter Setup 5-2