Fault phenomenon: it is found that both high speed and low speed speed are not stable.
Troubleshooting: the centrifuge is a DC motor speed control, the speed of the speed is through an adjustable resistance change silicon controlled through angle of the controllable silicon control rectifier after the arrival of two ends of the motor voltage, in order to achieve the purpose of speed control. Motor speed is not stable, from the principle of analysis, the following four conditions are possible.
1. Adjustable resistance, adjustable resistance due to the installation of the control panel on the use of very high frequency, a long time, the situation of poor contact is common.
2. SCR problems are also a lot of problems, usually the breakdown of short circuit, open circuit, can not trigger or internal poor contact, etc..
3. Four one of the rectifier diodes is only a problem.
4. Between the motor rotor and commutator with carbon or carbon brush itself bad.
