Replacing blown fuses on electric forklifts
Disconnect battery from forklift and discharge capacitor.
Remove covers to gain access to fuse panel. Control fuses are sometimes found under the dash. These will be Glass tube or blade type fuses.
Most electric forklift fuses are found in the area of the contactor or control panel. You will also find larger power fuses (35 to 500 amps). Below is a picture of fuses in a standup Yale ESC40-FA forklift. You'll see the fuses this truck uses are ANN80 fuses.
Here are photos of other types of fuses you may encounter on electric forklifts.
Visually inspect fuses looking for signs of heat (melted or discolored connections). If you have the glass fuses or fuses with a window you may be able to see an open or damaged fuse.
If you have access to a multi-meter (VOM), there are multiple methods to test your fuses. You can test using continuity mode or resistance mode. You must remove fuse from circuit in order to properly test using this method. You are looking for no resistance.
In rare cases a fuse may pass the visual test and continuity test but may still be the faulty. Fuses can sometimes have enough capacity to show continuity but will not carry current loads. The best method to test a fuse if you suspect this to be the case is to check for voltage. This can be dangerous if proper care is not taken. Be sure to block forklift so that it cannot move if drive circuit is energized unexpectedly. You must first plug in the battery. Always use care when working with live circuits. Locate the common negative terminal. Easily found by following the negative cable from the battery connector the first connection point on the forklift. Keep in mind that electric forklifts are not chassis grounded. Connect your negative lead from your VOM to this terminal. Now probe your fuses on both the supply side and the load side. You should get a reading that closely matches the voltage of your forklift battery at both points. For some control fuses you may need to turn the key on, sit on seat and release park brake in order to energize the circuit prior to testing. If you get the proper voltage reading on both sides of the fuse, the fuse is probably not the cause of the problem.
If you want to test the fuse even further you can test it under load. Be careful this can be dangerous if not done properly. If you do not feel comfortable please do not proceed. Fuses are inexpensive. Replace the fuse if you still suspect it is causing problem. If you work carefully, perform proper blocking methods, and be sure to have a clear working area you can energize the circuit and check voltage on load side of fuse. If voltage goes away when circuit is loaded, replace fuse.
Always replace fuses with the proper type, value and size. Improper fuses can cause extensive damage to other forklift components.
Keep in mind that if you find a blown fuse you should determine the cause to prevent further failures. Often power fuses are damaged from overloading such as pushing loaded pallets along the floor. If this is the case your forklift is working properly and some training is in order for your operator. If the operator is not the cause you should look for a shorted circuit or component that has caused the failure. See “How to check for shorted or open circuits”
Once all connections are made replace covers and reconnect battery. Test operation.
Congratulations! You have successfully repaired your forklift.