Operation

When the relay is switched  the high speed unit will operate inside 4 milliseconds followed

shortly after by the MVAA. The outgoing contacts of the two units are in parallel so to give

high speed and the breaking capacity. By using a low value resistor in parallel the 10 uF

capacitor discharge is overcome. As the MVAA 11 operates it switches out the MVAA16

and parallel resistor to lower the burden to an acceptable level.

Results

Pick up range: 87.5-  137.5V

Pick up time: 4 milliseconds  over voltage range

Drop off time: 15 milliseconds

Initial Burden  180 watts at 137.5 volts for 4 milliseconds  reducing  to 65 watts and finally

6.8 watts after 15 milliseconds.