the motor isconnected to the collecting main 58 and the terminal 22 of the motor 10 to the collecting main 53 in the circuit arrangement according to fig2 the motor unit 14 the reversing switch 30 and the central switch 90 are built up as in the circuit arrangement according to fig1 the control device 57 again has the inputs 76 78 79 and 80 and the outputs 55 56 and 59 the central switch 90 the reversing switch 30 and the motor unit 14 are connected to them in exactly the same way as in the circuit arrangement according to fig1 a difference to the version of fig1 is only to be seen in the interior construction of the control device 57 for there it is now done without a third relay in addition to the relays 70 and 71 the functions this relay had in the embodiment according to fig1 are now carried out by two additional switch contacts 100 and 101 of which the switch contact 100 isactuated by the relay 70 and the switch contact 101 by the relay 71 the switch contact 100 of the relay 70 is permanently connected to the output 56 and when the relay is excited connects this output to the input 78 such as the switch contact 73 connects the output 55 with the.