When the starter returns, it often encounters such a situation: after the switch is energized, there is no pull-in action, the motor is directly energized, no reaction, and the spark is small. After opening, it is found that the power tools commutator has been broken, together with the stator coil. The carbon brush holder is scrapped together. And this phenomenon is mostly out of the 24V car.
What is the reason for this?
Is the current too large?
Is the power on time too long?
The switch does not return?
Is the gear backrest too large?
What is the quality of the commutator of the rotor?
If the current is too large, the rotor will be burned directly. However, the maximum through current of the starter is basically the same. The maximum current of the four-cylinder machine will not exceed 650A. Why is there only a partial start-up opportunity?
Is the power on time too long? The starter is energized for too long, only causing the temperature to rise and burning the rotor, but the broken commutator has no signs of burning.
The switch does not return? After inspection, the switch returns to normal, and the switch contacts have no obvious adhesion marks.
Is the gear backrest too large? We have done experiments, the gears and the fixed rotation on the ring gear, the gears slip, can only bring the rotor to about 400 rpm, so the commutator will not be broken, but the gear of the fault starter is flexible and easy to use. It can be seen that the rotor has not been towed by the reverse direction of the gear.
The rotor’s own manufacturing defects? In fact, this is a difficult reason to determine. Perhaps this factor stands a little bigger.
Angu Electric believes that there is a comprehensive reason for the rotor to break up.
First we need to know the maximum speed of the eccentric four-cylinder starter. Generally, the maximum speed of a 12V starter is about 15,000 rpm, and the 24V speed will be higher than 17,000 rpm. Then, when the starter is running at high speed, a large centrifugal force will be generated.
But when the starter drives the engine to run, it will be lower than this no-load speed.
Tags: power tools commutator
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