Relay contacts operate with a snap action when disclosed electronic waveforms, profile its coil current. Snap action reduces the prolonged low pressure that damages
relay contacts. This means of driving the
relay coil also reverses the properties of its
voltage and current. Coil
voltage now varies with movement of its armature, frame current, coil resistance, back-EMF, and temperature. Coil current follows a profile that is stable and independent of these changing electrical, mechanical, and environmental factors. Since coil
voltage has no direct magnetic or mechanical effect its changes do not affect
relay operation. However the relays new stable current profile has a dramatic affect. It moves, makes, breaks and seats predictably, regardless of its temperature, residual
magnetism, or
mechanical wear. Power-line synchronization means takes
advantage of this new stability, concentrating on the position and pressure of the contact. The contact starts to move closed after the peak power-line voltage and makes at
zero voltage. Full
contact pressure is maintained until load-current is near zero and contact break occurs before zero current. Several types of coil current profiles are disclosed along with analog and
software controlled embodiments. New relay friendly electronic reset logic is disclosed to maintain
contact pressure during power losses caused by load-surge and load-shorts.
Zero crossing and power-line voltage are combined with logic that does not disable but delays relay operation.
Relay contact to coil
noise problems are disclosed along with suppression techniques to stop electronic circuitry induced contact chatter. Diagnostic techniques and production methods are disclosed for relays that are sealed inside an
enclosure. Automatic and manual timing adjustment means are also disclosed.