Priniciples of Electromechanical Relay Operation
3.17 Winding Circuit Design
Relays of the AC type are not ordinarily used, nor are they particularly well
suited, for complex switching circuits or for applications having critical
timing requirements. Usually the contacts of these relays are required only
to open and close reliably for the expected life under the specified load
conditions.
The information that is most essential in the application of ac relays is the
minimum voltage at which the relay will operate reliably. Assurance also is
required that the relay will release dependably. Usually the inspection and
evaluation requirements of the type discussed under the attributes method
(Chapter 4) will offer this assurance, provided the requirements are
representative of the worst circuit conditions. Ability of the relay to
withstand prolonged energization periods must also be considered.