Reasons and Solutions for Hydraulic Motor Failure to Start Injection Molding Machine


A、 Common reasons why hydraulic motors of injection molding machines cannot start 1. Power supply issue -Phase loss operation: When a three-phase motor loses one phase, the surge in current causes the protection to trip. A multimeter is needed to check whether the voltage of each phase is balanced. -Insufficient voltage: The rated voltage of the motor is usually 380V (three-phase) or 220V (single-phase). If the measured voltage is more than 10% lower than the rated value (such as three-phase voltage<342V), the motor may not be able to start. -Wiring error: If the phase sequence is reversed or the ground wire is loose, it may trigger safety protection. 2. Control system malfunction -PLC or frequency converter alarm: If "overcurrent" (E.OC) or "overload" (E.OL) is displayed, reset and investigate the load. -Contactor/relay failure: Contact erosion or coil breakage, require a multimeter to test for continuity. 3. Mechanical failure -Belt/coupling damage: When the motor runs idle due to breakage or slippage, it needs to be replaced (common belt models such as A and B, with a width of 12-20mm). -Transmission component jamming: Insufficient lubrication or foreign object jamming of screws or bearings can cause motor overload. Check whether the manual turning is flexible. 4. Protection device triggered -Fuse blown: Check if the specifications match (such as using a 30A fuse for a 15kW motor). -Thermal relay tripping: When the motor temperature exceeds the set value (usually 105 ℃), it automatically shuts off and resets after cooling.

B、 Targeted solutions 1. Mechanical troubleshooting -Clean foreign objects from screws or bearings and add lubricating grease (such as lithium based grease NLGI No.2). -Pay attention to tension adjustment (deflection 5-10mm/10kg pressure) when replacing damaged belts. 2. Handling power issues -Use a voltmeter to measure the input voltage. If there is any abnormality, adjust the transformer or contact the power supply department. -Re tighten the wiring terminals to ensure three-phase balance (deviation<5%). 3. Control system maintenance -Replace the burnt out contactor (such as CJX2-2510 type) and test whether the PLC output signal is normal. -Inverter parameter reset: After resetting to factory settings, re-enter the motor nameplate data (power, speed, etc.). 4. Preventive maintenance recommendations -Check the insulation resistance of the motor every month (≥ 1M Ω, using a 500V megohmmeter). -Clean the dust in the electrical control cabinet every quarter to avoid short circuits.

C、 Extended issue: Possible causes of abnormal noise during motor startup 1. Bearing wear: Pay attention to the model (such as 6205-2RS) when replacing. 2. Rotor sweeping: Adjust the air gap to 0.3-0.5mm (refer to GB/T 13957-2008). Through the above steps, 90% of motor start-up problems can be solved on-site. If it still cannot be processed, it is recommended to contact professional maintenance personnel or equipment manufacturers (such as Haitian, Zhenxiong, etc.) for technical support.

The above: What transmission components are used in injection molding machines?