XYZ AT4 VFD Parameter For Slow Start

[Barry Smith 4Participant @barrysmith4]

Hi, I have a XYZ AT4 vfd working on my mill at lower speeds on either winding and its fine. But on the 2 pole motor and the two highest speeds it blows the mains 240v 10amp fuse. So I guess the higher torque is causing an excess inrush current to blow the fuse. The derating on the drive is OK, but I guess the 10amp is probably marginal but not had this on other vfds I have installed in the workshop.

I need to check the current with a camp meter but thought I would try to find if I can set the right parameter to at least limit any startup current. I'm looking at p24- overload protection buffer time, p34 -main rising velocity and p66-input stabilization time. Has anyone any advice on the best parameter to change?

Thanks

Barry

[Barry Smith 4Participant @barrysmith4]

[Martin ConnellyParticipant @martinconnelly55370]

Have you considered limiting the maximum voltage? On my AT1 it is parameter 00. This may result in lower current, I am only guessing that this is the effect as I have not changed it to see what the effect is. Obviously it may reduce available torque but it may be something to try and see what the result is. i would expect it to only change the torque at high RPM where torque may not be such an issue as you are likely to be using small diameter cutters.

Martin C

[Barry Smith 4Participant @barrysmith4]

Hi, I have played around with P34 (main rising velocity) the default states 10 hz/s. Mine was set at 5 so changed it to 2 Hz/s and seems to have worked. Monitoring the 240v ac in gives less of a peak and just keeps below 10amps. Running at 50H the motor is taking 8amps. Looking at the 380v line it gives around 4amps which sounds about right on one of the phases.

I am measuring amps with a clamp meter that gives 100mv per amp, so not sure if that's rms or not.

Barry

[John HaineParticipant @johnhaine32865]

If you mean a clamp on current transformer, whatever you measure the volts with it's the same – rms or peak.

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