Motor drive

A motor drive includes a rectifier bridge, which rectifier bridge is connected to an DC link, which is connected to an inverter bridge having phase outputs configured to be connected to an elevator motor, as well as a drive control controlling the semiconductor switches of the inverter bridge. The inverter bridge has upper semiconductor switches of the upper side connected to plus of the DC link and lower semiconductor switches of the lower side connected to minus of the DC link, the upper semiconductor switches are semiconductor switches without desaturation- and/or over-current protection whereas the lower semiconductor switches comprise a desaturation- and/or over-current protection, or vice versa. The drive control includes an earth fault control circuit which is configured to establish an earth fault test, in which each single semiconductor switch comprising a desaturation- and/or over-current protection is switched through, only one at a time, over a test time period, whereby the earth fault control circuit is configured to enable start of the motor drive only if the earth fault test has not lead to a tripping of the desaturation- and/or over-current protection of one of the semiconductor switches.