How to solve vibrating noise (Cause: low voltage across coil) of magnetic contactor

[abdurrahman.iit]

I have design a Auto Transfer Switch (ATS) for switching between 2 power source. Suppose, one power source is named as A which is used as main source & it always supplies approximately 215VAC to 235VAC and another source is named as B which is used as emergency source & it always supplies approximately 150VAC to 215VAC. There is used 2 magnetic contactors (Hyundai HMX22) and 1 relay in my ATS. As main power source (named as A) always supply above 200VAC, so the magnetic contractor interfaced with this moves the armature ( trigger/switch ) properly and faster. But As the emergency power source (named as B) most of the time supplies less then 170VAC, so the magnetic contractor interfaced with this does not move the armature ( trigger/switch ), its just continue vibrating noise. How can I make my ATS workable for mentioned 2 power source? What are the changes or modifications required?

My experiments:
1. when the coil of magnetic contactor is energized by above 185VAC, it moves the armature ( trigger/switch ) properly.

2. when the coil of magnetic contactor is energized by less then 180VAC, it does not move the armature ( trigger/switch ) properly. ), its just continue loud vibrating noise.

 

[Bluejets]

Contactor coil is obviously 220vac and the contactor is designed for that level, not 180vac.
Tolerance is normally around 5% maximum, run it on less and you'll cook it as well as what damage I can only imagine would happen to the contacts and the load.