Abstract: An apparatus for testing enclosed electromagnetic relays includes a probe displaceable into the relay enclosure to engage the movable contact thereof. The probe is associated with a force transducer and a displacement transducer which provide inputs to a circuit including microprocessor unit which operates to detect the probe force required to break contact between the movable contact and the normally closed contact and to detect the position of the probe when such break occurs and when the normally open contact is made and to calculate the contact travel from the position signals it receives. Contact over travel is also measured by applying current to the relay winding and measuring probe displacement required to re-engage the contact.

Abstract: A battery isolator switch has main battery contacts and an auxiliary contact for controlling the supply of excitation current to an alternator. In order to ensure that there is a delay between opening the auxiliary contact and the main contacts when the switch is tripped by a remote contact, there is provided a latching circuit which energizes a relay for opening the auxiliary contact, and a delay circuit for turning on a transistor after a suitable delay, to energize a main tripping winding via another relay.

Abstract: An electrically assisted pedal power vehicle includes a rotation sensing arrangement sensing the direction of rotation of a rotary drive member in the pedal propulsion mechanism of the vehicle. The rotation sensing arrangement includes a pair of switches actuable by means on the drive member. The switches control a monostable circuit such that the circuit produces an output pulse only when the switches are actuated in the correct order. A frequency to voltage converter may be driven by the monostable circuit with a Schmidt trigger sensitive to the output of the converter controlling the electric drive motor.

Abstract: In order to be able to use a standard windscreen wiper switch with a biased open contact for selecting flick wipe or intermittent wipe operation the control circuit includes a flip-flop which is set when the contact is closed, but is reset by a timing circuit if the contact is held closed for more than a predetermined time. The output of the flip-flop controls a timer i.c. which in turn intermittently energizes the wiper system while the flip-flop remains set.