Why is it necessary to gradually increase the load when starting a reciprocating compressor, and can it be started directly?
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Why do reciprocating compressors need to increase the load step by step at 0%, 50%, 75%, and 100%? Can’t the load be set to 100% before starting the machine, and the machine started directly using the pressure changes in the air valve to open or close it?
Protect the motor, improve operational stability, prevent bearing burnout, and more
According to Newton’s laws, for an object to go from rest to motion, an external force must be applied in order to overcome its inertia. When a reciprocating compressor is started at full load, the pressure at each piston end creates a significant resistance that prevents the motor from rotating. The power it requires is far higher than the rated value of the drive, which will inevitably damage the drive.
There is no need to load it up step by step, but it is essential to operate it at zero load until it runs stably before increasing the load to full capacity. This is because many compressors do not have a regulation mechanism that allows the suction valve to be opened at pressures of 0, 50, or 100; they operate with the circuit fully open when started, and once they are running steadily, the circuit is closed for full-load operation.
Starting the compressor at full load directly causes significant damage to it; it’s similar to driving over a speed bump while the vehicle is in motion versus starting the vehicle while going over such a speed bump – the amount of power required in each case is different. Starting at full load results in a high piston force at the moment of startup, and the current seems to be much higher than normal as well.
Starting the engine under load increases the starting torque and the motor power. The principle is similar to starting the pump with the outlet of the centrifugal pump closed
Protect the motor from excessive starting current
Do not operate at full load directly; follow the equipment’s operating procedures, as otherwise it constitutes illegal operation. We’ll deduct your performance score, cut your bonuses, issue a reprimand to you, and make you pay for the damaged equipment! Be a good employee who understands equipment, processes, and safety.