TECHNICAL REFERENCE
453
June 1999
96-8000
12.7 TWO-SPEED G EAR T RANSMISSION
The spindle head contains a two-speed gear transmission. The spindle motor is directly coupled to the
transmission and the transmission is cog belt-coupled to the spindle.
GEAR B OX L UBRICATION
Gear Box: Mobil DTE 25 oil.
The gear box uses an oil sump and is cooled by gear oil. The VF-0/E/OE does not have a gearbox and is air-
cooled.
GEAR B OX A IR S OLENOIDS
There is a double solenoid valve controlling air to the gear box shifter. This solenoid sends air to select either
the high gear or the low gear. When power is removed from the solenoids, the valve remains in its last state.
Air is always required to ensure the gears are held in either high of low gear. Circuit breaker CB4 will interrupt
power to these solenoids. Power is left on the solenoid which is commanded last.
On machines equipped with a 50 taper spindle, an electric motor drives the gearbox shifter into high or low
gear.
GEAR B OX S ENSE S WITCHES
There are two switches in the gear box used to sense the position of the gears. One switch indicates HIGH by
opening and the other indicates LOW by opening. Between gears, both switches are closed indicating a
between-gear condition. The diagnostic display shows the status of these switches and the CURNT COMDS
display shows which gear is selected. If the switches indicate that the gear box is between gears, the display
will indicate îš“No Gearîš”.
GEAR C HANGE S EQUENCE
When a gear change is performed, the following sequence of events occurs:
1) If the spindle is turning, it is commanded to stop,
2) Pause until spindle is stopped,
3) Gear change spindle speed is commanded forward,
4) Pause until spindle is at speed,
5) Command high or low gear solenoid active,
6) Pause until in new gear or reversal time,
7) Alarm and stop if max gear change time elapsed,
8) If not in new gear, reverse spindle direction,
9) Turn off high and low gear solenoids
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