Working Principle of Electromagnetic Start Switch for Generating Set

Working Principle of Electromagnetic Start Switch for Generating Set

There are two kinds of control switches in the electric start system of generator set: electromagnetic type and mechanical type. The electromagnetic switch is driven by the electromagnetic force to pull the fork to start. When starting the diesel engine, press the switch. At this time, the circuit is as follows: the battery switch, the connecting post 5, the iron absorption coil, the connecting post, the generator and the iron battery. The current flowing through the iron suction coil makes the core magnetized to produce suction force, and the moving contact is sucked down and closed with the static contact. At this time, the circuit flowing through the starting switch is as follows: the battery terminal 4 moves the contact point and the static contact keeps the coil; the attracting coil is connected with the pole 3 and the starting line of the starter is equipped with an iron storage battery.

At this point, the current flows through the DC motor, but because the current is very small, the motor can not rotate. The direction of current flowing through the coil is the same as that of holding the coil, and the magnetic flux is the same. Therefore, a strong magnetic force is synthesized to draw the moving iron core to the left and drive the fork to engage the starting gear with the flywheel. At the same time, push the copper sheet to the left compression reset spring.

When the active core is moved to the left extreme position, the copper sheet connects the circuit between the terminal 3 and the terminal 4. At this time, a large amount of current flow into the DC timing line, motor rotation, into the starting state.

After startup, the switch is released, the current in the coil is cut off, the core pushes the suction force, the dynamic contact jumps away, and the current between the holding coil and the suction coil is cut off through the dynamic contact and the static contact. The circuit in the switch at this time: the storage battery is connected with 4 pieces of copper bar and the third pole attracts the coil to hold the coil and tie the iron battery.

Because the current in the coil is drawn in the opposite direction, the magnetic flux produced by the coil is opposite, and the magnetic force counteracts each other, resulting in the suction of the moving iron core, and the active iron core drives the starting gear back to the original position under the action of the reset spring. Cut the circuit between Pillar 3 and Pillar 4 and stop the motor.

What should be paid attention to in the automatic Air switch of the Control Panel of Diesel Generator set

1. Correctly select rated current of release

In the case of an automatic air switch of DZ10-100 type, the main contact allows for a long period of time to pass through 100A rated current. Which to coose depends on the capacity of the generator. If the generator used is 30KW and the stator current rating is 54.1A, the release with rated current of 60A should be selected as close as possible and slightly larger than the rated current of the stator. If the current is too large as 80A, if the generator is overloaded for a long time and the heat release does not work, the automatic air switch can't protect the generator from overload. If 40A is selected, the generator is rated for about 1 hour, and the release takes place, which causes the automatic air switch to trip and cause the power failure. The rated current of the release should therefore be specified at the time of purchase.

2. Correct selection of instantaneous Action rated current

The rated current of instantaneous action is selected according to the result of short circuit calculation. The setting value of the current should be set by the switchyard, and the requirement must be put forward to the manufacturer when ordering, otherwise, the maximum value should be set when leaving the factory. In general, the instantaneous operating rated current of the automatic air switch purchased in the store does not meet the requirements and, if necessary, an additional short circuit protection device is added.

The main switch of the diesel generator set control panel can not be closed

The main switch of control panel of diesel generator set refers to the automatic air switch of primary loop. What are the reasons for the failure of the main switch and how to deal with it?

I Manual operation, main switch can not close

1. Under-voltage release coil has not voltage, or coil joint contact bad or broken wire, burned. Power should be plugged in to repair or replace coils.

2. The gap between the armature and the core of the undervoltage release is to large, so it will not be absorbed after the power is turned on.

3. The operating mechanism is not in place, each axis in the mechanism is nor flexible or the top of the lever has burr. Adjustment of bottom, coaxality between panels, lubricating oil. Grind the top of the lever, deburr, and lubricate.

4. The underpressure release lever is adjusted too high, which causes the screw on the half shaft to move up. The armature of the shunt release is not reset or the push rod on the release shaft is too high. The occlusal amount of lever and half axis was more than 1.2 mm.

II Electric operation, main switch not closed

1. Press close button, relay does not work

Generally, the button is in poor contact, the relay coil is broken, the relay auxiliary contact is normally closed to be normally open or diode, and the capacitor is broken. The repair method is: repair or replace the button; connect the disconnection or replace the coil; correct the relay contact wiring Replace damaged diodes and capacitors.

2. Relay action, main switch cannot be closed

The bridge rectifier diode is burned and the electromagnet coil is broken. The diode should be replaced, connected to the wire break or the coil replaced.

3. Press the button, the relay is closed, but the main switch can not be closed.

The electromagnet rod stroke is not enough or the electromagnet rod bolt is loose. Adjust the gap between the moving iron core and the bracket to ≤0.5mm, and tighten the bolt.