What Is Acceleration Time For "small" (6.6kw) Motor

I do electro hydraulic design and troubleshooting, also performing technical services on EH systems.

I'm working on one where I seriously question the design; both measurements and calculations show the motor cycling on to maintain pressure for under 0.1 seconds. This does not normally occur often, but occasional hydraulic problems have this cycling occurring about every 3 seconds. How do you spell warm?

(PLEASE DON'T SHOOT THE MESSENGER!)

I am trying to gain some general feel for the time to start a "typical" small squirrel cage motor across-the-line and to determine if the user without the motor manufacturer's inertia data can calculate that (I'd probably ASSUME starting power of 4* running as an approximation over the acceleration time, initially perhaps 7* dropping as speed increases.) But to add to the "less smart design", it starts for this "plug" at full shaft torque in addition to the inertial torque.

This motor, FWIW, is a 112M-B5 6.6kW 4P 480/3/60. My personal feeling is that it will probably reach 95% speed in under 0.5 sec ... supply is satisfactorily stiff.

There are a lot of things I would have done differently, but let's not go into those; I don't have redesign or replacement options, just explanation of what is happening so a manager can make an informed decision.

I've worked with medium frame motors where 10 seconds would not have been unreasonable ... limit of 3 starts then cool for an hour ... this isn't that type of application.

Any guesses? Any answers?

Thanks! George, South Carolina USA