Rockwell Automation WebPak 3000 DC Drives Hardware Reference, Installation and Troubleshooting - Manual (Page 52)

4-10 WebPak 3000 DC Drive Hardware Reference
4.7 Adjusting the Tachometer or Encoder Loss Sensitivity
Normally, tachometer or encoder loss is reported when the SCR firing angle reaches 109° when
armature current is present and the speed feedback is less than 5% of GEAR IN SPEED
(P.011). If you are getting nuisance trips associated with high inertia loads, you can adjust the
SCR angle at which tachometer or encoder loss is reported.
For a description of parameter TACH LOSS SCR ANGLE (P.608), refer to the WebPak 3000
Software Reference manual.
ATTENTION: This equipment is at line voltage when AC power is connected to the
drive. Disconnect and lockout incoming power to the drive before proceeding. After
power is removed, verify with a voltmeter at power terminals 1U, 1V and 1W that
no voltage exists before touching any internal parts of the drive. Failure to observe
these precautions could result in severe bodily injury or loss of life.
If you are getting nuisance tachometer or encoder loss trips:
1. Lockout and tag power as necessary.
2. Turn off power to the drive.
3. Check all tachometer or encoder lead connections, including polarity.
4. If there is no problem with the connections, increase TACH LOSS SCR ANGLE by 1 degree.
5. Restart the drive.
6. If a tachometer or encoder loss is reported and the angle is less than 127°, repeat this
procedure.
4.8 Phase Locked Loop (PLL) Maximum Error
If your drive power is supplied by a source that cannot maintain a suitable fixed frequency
output (such as an alternator), you can adjust PLL MAXIMUM ERROR (P.308) to prevent faults
related to line synchronization.
For a description of parameter PLL MAXIMUM ERROR, refer to the WebPak 3000 Software
Reference manual.