Identify the INCORRECT application of attracted armature type electromechanical relay?

Attracted Armature type electromechanical relay:

• It is the most simple both in construction as well as in its working principle. These types of electromagnetic relays can be utilized as either magnitude relays or ratio relays. These relays are employed as an auxiliary relay, control relay, over current, undercurrent, over-voltage, under-voltage, and impedance measuring relays.
• Hinged armature and plunger-type constructions are most commonly used for these types of electromagnetic relays. Among the two constructional designs, the hinged armature type is more commonly used.
   

Construction of Attracted Type Relay:

• This relay is essentially a simple electromagnetic coil and a hinged plunger.
• Whenever the coil becomes energized the plunger is attracted towards the core of the coil, Some NO-NC (Normally Open and Normally Closed) contacts are so arranged mechanically with this plunger, that, NO contacts become closed and NC contacts become open at the end of the plunger movement.
• Normally attraction armature type relay is dc operated relay. The contacts are so arranged, that, after the relay is operated, the contacts cannot return to their original positions even after the armature is de-energized. After relay operation, these types of electromagnetic relays are reset manually.