19
ROTOR TIMING
Rotor timing must be precisely maintained to provide maximum pumping efficiency, yet prevent
contact between rotors during operation. If pumping efficiency is below expectations, or if rotors
contact during operation (within rated differential pressure), check rotor timing and adjust if
incorrect. Also check rotor timing after any gearbox dismantling when the gears are removed
and/or replaced.
Check Rotor timing as follows:
1. Assemble each rotor (1.1) in its normal location on the drive shaft and the idle shaft.
Assemble each rotor bolt (3.5) and tighten hand tight.
2. Rotate the shafts 30 degrees and measure gap as illustrated by arrows. Rotate the shafts 60
degrees the opposite direction and measure gap as illustrated.
3. The Rotors are correctly timed when the gap measured at both locations are equal. If the
gap is unequal, adjust the timing as follows.
4. Rotor timing is determined by the relative
location of the two helical gears (3.2) on
the shafts.
5. Place the wooden dowel between
the rotors.
6. Bend away the tab of the lock washer
(3.3) on one shaft. Loosen the lock
nut and temporarily insert shim stock
between the gear and gear spacer.
Tighten the lock nut, reassemble the
rotor in its correct location, and
recheck rotor timing.
* If Rotor timing is correct, remove the gear and replace added other spacer or add a shim
equal in thickness to the shim stock temporarily added. Reassembly the gear and gear nut,
tighten to the correct torque, and check rotor timing again to confirm that it is correct.
* If rotor timing is incorrect, but closer to equal than original measurement, repeat previous
step adding addition shim stock.
* If rotor timing is incorrect and more unequal than original measurement, remove temporary
shim stock from one shaft and add instead to the other shaft.
7. Repeat above procedures until the timing gap is equal after gear spacers are in place and
gear nuts are tightened to correct torque.
8. Reassemble pump.
Fig. 25
Summary of Contents for AccuLAB Series
Page 1: ...Operating Maintenance Manual JEC AccuLAB Series Rotary Lobe Pumps...
Page 4: ...3...
Page 5: ...4...
Page 6: ...5...
Page 7: ...6...
Page 23: ...22 DIMENSIONAL DRAWING FOR BARE SHAFT...
Page 24: ...23 PARTS LIST EXPLODED VIEW...