Product Description
Diode Assembly For Pump Contcr
Frequently Asked Questions
Q: What does the CR 128939 diode assembly control in a pump contactor circuit?
A: The CR 128939 diode assembly is part of the pump contactor circuit in Crown electric lift trucks. It functions as a rectifier or protection device that regulates current flow and prevents reverse voltage spikes when the pump motor is switched off. This protects the contactor contacts and electrical control components from arcing and premature wear.
Q: What symptoms indicate a failed CR 128939 diode assembly?
A: A failed diode assembly may cause the pump to operate intermittently, erratic pressure readings, or inability to engage the pump contactor. You may also observe visible burning or darkening on the contactor terminals, or electrical arcing when the pump is switched. The contactor contacts may show accelerated pitting or erosion.
Q: Can the CR 128939 be tested or does it need replacement?
A: Diode assemblies are solid-state components without user-serviceable parts. Testing requires specialized electrical equipment. When failure is suspected, replacement with a new CR 128939 is the correct action. Do not attempt to repair or bypass the diode assembly, as it is critical for contactor protection.
Q: How often should the CR 128939 be replaced as maintenance?
A: The CR 128939 diode assembly does not require routine replacement. It is designed to last the operational life of the equipment under normal use. Replace it only when symptoms of electrical circuit malfunction appear, such as contactor chatter, pump control issues, or visible arcing in the contactor assembly.