HVAC VFD Accel/Decel Commissioning

When I am commissioning a general VFD that is used on pumps and fans. 

I prefer to set my accel/decel time to 90/60 seconds. 

Please keep in mind that this is a general statement and not appropriate for every situation. 

If this time is set incorrectly then the drive reaction time can conflict with the controls speed PID. 

This is true whether you go too fast or slow. 

Many drives ship with a 30 second acceleration time and 10 second deceleration time. 

This default can work fine at times. It is my opinion that it's a bit fast for most situations and adds addition wear to the stator. 

The faster the ramp is the more stress is being put on the stator. Like everything though there are limits to this. 

The slowest I will typically ever go is 120/90 seconds accel/decel. 

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