Prepared by: RJG Rev. #: A
Revised by: JAF Date: 03/23/12
Approved by: WAH 1200644
Revision Date:14AUG13
Trapped particulate entrained in air gap (between armature assembly and
friction material)
Damage or Failure of 1, 2 or all 3 of the clutches spring plates.
These plates hold the pulley sheave to the armature assembly,
transferring rotational energy of the pulley sheave through the belt
drive to the clutch friction material (when the clutch coil is energized)
and correspondingly through the primer rotor/shaft assembly creating
a vacuum in the rotary vane primer pump. These spring plates allow
for this transfer as well as allow the energized clutch coil to overcome
the spring force in these plates and close the air gap between the
armature assembly and the friction material, or vice versa re-
establishing the air gap and preventing the belt drive system from
transferring rotational energy to the rotary vane primer pump.
- Excessive belt wear
o Could be indicated by:
Misalignment between Driver and Driven pulleys
Axial or Angular
Revisit the primer assembly drawing and contact W.S. Darley Customer
Service if necessary. Belt drives must have nearly zero misalignment
for long life and proper function.
- Minimal vacuum creation by Primer
o Damaged vanes
o Loss of original lubrication in primer rotor housing and vanes
o Particulate trapped in vane housing
Causing vane(s) not to fully engage and disengage in vane housing/rotor
Would prevent vacuum creation or severely inhibit such
- Other challenges may occur that have not been listed here, we kindly ask that you document
these challenges as best you can and contact W.S. Darley Customer Service to identify the
root cause and evaluate any necessary changes in the design.
For challenges and assembly/disassembly assistance:
CONTACT DARLEY CUSTOMER SERVICE IMMEDIATELY AT 1-800-634-7812 or 715-
726-2650
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