Regarding the maximum continuous speed and trip speed of centrifugal compressors
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As the title suggests, it concerns the maximum continuous speed and trip speed of centrifugal compressors. On the nameplate, these values are given as a single figure; I’m not quite sure what this means. I hope those with more experience can explain it to me
The maximum continuous speed of a centrifugal compressor refers to the highest speed at which the compressor can operate continuously under normal operating conditions. The tripping speed generally refers to a threshold set by the safety device; when the compressor’s rotation speed exceeds this value, the safety device intervenes automatically to shut down the compressor, thereby preventing possible mechanical damage or other hazardous situations. If the maximum continuous speed and the tripping speed indicated on the nameplate are the same value, this may mean that the compressor was designed with the maximum safe operating speed set as the threshold for the trip protection. The purpose of this is to ensure that the compressor under no circumstances operates at speeds that could cause mechanical failure or excessive wear. This design can be understood as a safety measure aimed at shutting down immediately once the maximum designed speed is reached, in order to prevent any possible overload or damage. .
There’s nonsense written upstairs; it’s clearly defined in API617
Maximum continuous speed: The highest speed at which the machine can operate continuously after being manufactured and during testing. For compressors driven by variable-speed drives, this speed is 105% of the rated speed.
Tripping speed: The independent overspeed emergency device activates to stop the speed of the variable-speed drive. For this standard (API617), except for variable-frequency drive units, the tripping speed of an AC motor is the speed (r/min) corresponding to the synchronous speed of the motor at the maximum supply frequency.
It’s just that the ratios are different; one is 105% and the other is 115%.
Maximum continuous speed: The highest speed at which this machine can operate continuously after it has been manufactured and during testing. For compressors driven by variable-speed drives, this speed is 105% of the rated speed. For compressors driven by motors with a constant speed, this speed depends on the synchronous speed of the motor. Trip speed (in r/min): The speed at which an independent overspeed emergency device activates in order to stop the speed of the variable-speed drive. For this standard, except for variable-frequency drive devices, the tripping speed of an AC motor corresponds to the synchronous speed of the motor at the maximum supply frequency
It should trip when it reaches the maximum speed; if it doesn’t trip, it will overspeed and an accident could occur.