Novaturn Spindle Speed Very Low

[boots]

Novaturn 1998
S/N eo5234
VR Turning v1.9
Windows XP

Problem:
The spindle turns at a very low RPM (apx 100) even when the speed in the control panel is increased to 3500.
The machine does not have Feed or Speed Over Ride knobs.
We went into the Machine parameters and Unchecked the feed and speed pots. Tried it with the boxes checked also.
The machine was working fine about a week ago, but the last time it was used the rpm changed and went way up, like it was set to "Constant Surface Speed Mode (g96). It was NOT set in that mode and we where just turning a piece of bar stock to a set diameter.

Is there a RPM sensor or is the Encoder faulty?
What needs to be checked and what are we looking for? (voltages, signals, etc.)

[bradders]

FYI
1. If the spindle runs at its top speed all the time, then it will probably be a faulty Tachometer.

2. If the spindle is not running at the speed selected, go into the COORDINATE DISPLAY CONNECT button in VR Turning and check the actual speed and against the the programmed speed, if there is a difference then it could be a faulty encoder

3. If the spindle is running slow check the Analogue voltage out of the control card. See the link below, they are the Red and Blue wires on the bottom left hand side of the board. The voltage range is 0 -10v DC. Select spindle start and vary the speed knob and see if there is any variation in the analogue voltage out of the board, if not, the analogue on the board is faulty.

viewtopic.php?t=325&highlight=analogue