When rapidly lowering hoist block, hoisting stops – HDT 80

With the addition of the hoist drive on the HDT 80, during rapid lowering, drive may fault and need reset.  Drive displays Ou (Ov- overvoltage)  Changed parameter C1-02 (deceleration time 1) from.8 seconds to 1.2 seconds.

This is an overvoltage of the dc bus because with a decending load the hoist motor may act as a generator and overcharge the dc bus.  The braking resistor may be undersized and the dc bus cannot discharge fast enough.  This parameter change allows for a slower deceleration to discharge.