Troubleshooting Common Chain Hoist Problems
A chain hoist is used to lift or lower a load. It has an electrically powered motor with a drum of wheel that has a chain wrapped around it. The load is attached by a hook. This piece of equipment is the workhorse of many workshops. When it is not working properly then you can troubleshoot the issue.
Hoist Does Not Lift or Lower
One possible cause is that the emergency stop button is on or the mainline switch is shut off. Next check for a blown fuse. Replace the fuse if necessary. The next thing to check is that the motor may have overheated and needs to cool down. If these steps don’t resolve the problem then check to see if the pendant plus pin is pushed out or if the contractor terminal screws need to be tightened.
Hoist Cannot Lift Load
If the hoist is overloaded then reduce the load. If that is not the issue then check to see if the slip clutch worn or incorrectly adjusted. If so replace or readjust the clutch torque. Another problem may be that the brake is not releasing. Check the brake coil resistance, gap setting and rectifier output voltage.
If the load drifts more than 4 inches the brake lining may be worn and needs to be replaced. If the air gap on the brake is too wide, adjust the air gap setting.
If the chain host makes strange noises while lifting or lowering, the chain may need to be cleaned and lubricated. Check the load chain or idler sprocket for wear and replace if necessary. See if a supply phase is missing. If so, then connect the three phases. Finally inspect the load chain for kinks or twists.
Invert Does Not Start
If the inverter does not start when the mains are connected, check the voltage between the terminals.
Motor Does Not Run
If the ready indicator is on but the motor will not run, check the control mode selected. Also check the voltage at the run command terminals and the digital inputs. Another connection to inspect is the motor cable connection.
Motor Runs Poorly
If the motor is running but not performing well, see if the load is over the nominal limit and that all cables are connected. Check the voltage of the lowdown limit switch input and the digital inputs. If there is still a problem, be sure that the motor brake is open completely. Lastly the minimum speed parameters may be set too low.
Motor or Brake Overheating
If the motor or brake is overheating then the load may be excessive and need to be reduced or the frequency of use may need to be reduced. Check the voltage and frequency of the power supply and make sure it complies with your specific hoist. If the external temperature exceeds 140 degrees F, the hoist should be ventilated or shielded from the heat source.
Inspect the collectors to see if they are making contact and see if the contacts are arcing and need to be replaced. Check for a loose connection in all wires and terminals in the circuit and replace if necessary.
For other issues consult the operator's manual and the manufacturer if necessary.