1. Causes of Runaway of Electric Tricycles
The failure phenomenon of runaway is that after the power lock is turned on, the motor of the electric tricycle runs at a high speed.
At this time, it is very dangerous to ride it, and it should be repaired in a timely manner. (1)Most of the runaway failures are caused by damage to the controller (damage to the power MOS transistors inside the controller). (2)Damage to the throttle grip (broken ground wire of the throttle grip or the throttle grip cannot return to zero) can also cause runaway.
2.Maintenance methods for runaway failures
① Check whether the ground wire of the throttle is broken. If it is broken, reconnect it and seal it with insulating tape.
② Turn on the power lock and rotate the throttle. Use the DC voltage range of the multimeter to measure the voltage of the throttle signal wire. Under normal conditions, it should vary from 1V to 4.2V. If it remains at 4.2V without change, it indicates that the throttle is damaged and a new one should be replaced.
③ If the throttle is in normal condition, check the controller next. Rotate the throttle and use the DC voltage range of the multimeter to measure the output wire voltage of the controller. Under normal circumstances, it should vary from 0V to 40V. If it remains at 40V without change, it indicates that the controller is damaged and a controller of the same model should be replaced.
repair the controller
④ If you want to repair the controller, you can use a screwdriver to open the outer casing of the controller.
⑤After opening the outer casing of the controller, use the diode range of the digital multimeter to measure the three pins of the MOS transistor. If the MOS transistor is short-circuited, the measurement result will be 0 ohms. If the MOS transistor is damaged, the fault can be eliminated by replacing the components of the same model.
⑥ Use an electric soldering iron and a desoldering pump to remove the MOS transistor. Since most controllers adopt double-sided circuit boards, pay attention not to damage the circuit board when removing the MOS transistor.
⑦ Install the MOS transistor of the same model and solder it with solder. It should be noted that generally the MOS transistor is fixed on the outer casing of the controller, and there is a mica sheet padded behind the MOS transistor. Pay attention to its proper installation.
⑧ Restore the wire harness near the controller and conduct a test run.
