Chapter One: The introduction of electrical system and exclusion methods for impossible troubles-II. The introduction of electrical elements-9


Malfunction 5, all motor cannot be started.

Failure 5-1: the control circuit of the control button is loose or disconnected. In this case, no input signal in the PLC input terminal, the corresponding indicator is not ON.

Solution 5-1: Check the control wiring to solve the problem. In this case, check the PLC input terminal and COM voltage, if there

is  no input voltage, it might be the control circuit disconnected  or no 24V power.

Failure 5-2: The intermediate relay circuit board (220v)

is damaged or disconnected. In this case, the PLC input and output terminals indicator is ON and has output signal, but the intermediate relay indicator is not ON, the AC contactor does not pull.

Solution5-2: Check the intermediate relay circuit board, repair

or replace it.

In this case, the PLC input and output terminals  indicator  is ON, and has output signal, the intermediate relay indicator not ON. Failure 5-3: 220V control circuit  disconnected  or  no  220V power. In this case, the PLC input and output terminals indicator is ON, and has output signal ,but the intermediate relay indicator is ON, while the AC contactor does not pull, the motor does not work. Solution 5-3: Check it and repair. (Check the transformer, fuse and

220V power lines.)

Malfunction 6, The indicator on all solenoid valves cannot be on; the hydraulic movement cannot be action, but the proximity switch indicator is normal.

Failure 6-1: electronic control box to the 24V control circuit of the relay circuit board is disconnected, the solenoid valve coil is energized, does not work.

Solution 6-1: Check the electrical control box +24 V and COM lines.

Failure 6-2: The control circuit outside electrical control box is disconnected, such as aerial wires or junction box on the +24 V and COM line is loosen.

Solution 6-2: Check the external power supply circuit.

Malfunction 7, All movement not available.

Failure 7-1: 220 V control circuit is disconnected or no power, no input voltage in the PLC.

Solution 7-1: Check the 220V power line. (If the transformer damaged no 220V power output; 220V get burned; lightning

protection to protect the 220V control circuit get burned.)

Failure 7-2: PLC switch doesn’t open or the PLC gets damaged.

Solution 7-2: Check the switch and the PLC.

Failure 7-3: Equipment locked or oil temperature, filter alarm protection.

Solution 7-3: Check the touch screen alarm, if so, re-set the parameters on the touch screen to cancel the alarm.