I have just got a 1 KW electric motor with gearbox from E bay, it was advertised as single phase but when it arrived today I found that it was a Tornado G90/120 compound wound DC motor with the armature voltage at 150 and the shunt field 280 volts. I want to be able to reverse the motor which would mean not only reversing the armature or shunt field but also reversing the series field in relation to the armature, I was wondering in order to simplify switching could I safely leave the series field out of circuit, the motor will only run for about 30 seconds a time and no where near 1 KW power is required for the job as the original motor was only 12 volts at about 40 watts. The reason I am fitting such a big motor is I am fed up with replacing motors on this sliding gate due to the end of the shaft which is 10 mm dia. breaking off as soon as the weather gets cold, I have fitted 5 motors in as many years to date. I am hoping that running without the series field will not lead to motor burn out, myself I cannot see a problem due to the short run times but other opinions are very welcome.