The impact of variable-frequency motors on air valves in reciprocating compressors
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If a reciprocating compressor is changed from an original synchronous motor to an inverter-driven motor, resulting in a decrease in speed and a reduction in the amount of air drawn in, what impact will this have on the air valves? If the speed decreases, calculations show that the opening and closing angles of the air valves will increase. What effect will an increase in these angles have on the air valves – a positive one or a negative one? Also, apart from the air valve, could it have an impact on other parts as well?
I’ve never seen compressors with variable frequency control; such control is quite common for reciprocating pumps
Compressors are rarely used, but this is a viable option; it has many limitations.
It is unrealistic to change the frequency of a reciprocating air compressor
Why isn’t the air compressor a viable option? What are the special features of an air compressor?
I was mistaken; reciprocating machines can achieve variable frequency, and it has no impact on the air valves. There are only 2 issues: 1) If it’s a small machine, then it’s not necessary. The rotation speed of large machine motors should not be too low; if it is, the motor’s torque becomes excessive, which can cause heating and affect the motor’s lifespan. Generally, synchronous motors operate at 50 hertz, and variable frequency motors should not exceed 50 hertz either.
Reciprocating machines can achieve variable frequency without any impact on the air valves. Disadvantages: High cost of frequency conversion, many vulnerable components; it is better to use a continuously variable control system, which is energy-efficient and less costly.
I’ve never seen a reciprocating compressor with a frequency-changing motor, but I have seen ones where the air valves were replaced with a variable-volume control system~~~ That approach seems more reliable than changing the motor; with an initial investment, the energy savings can cover the cost over several years
Variable-frequency pumps are used quite frequently; compressors have not been seen in this context. Generally, it is the unloader that is used to adjust the air valves, enabling adjustments to levels of 30%, 50%, 70%, etc.
It is beneficial to replace the original synchronous motor with an induction motor.