TVS Diode and Relay Circuit

What is your coil resistance of the relay in your circuit?

I understand what you are trying to do, but the coil resistance of your relay in DC is probably less then 200ohms. With the 1K series resistor I doubt if you will achieve pull in current, and the capacitor will drain very fast through the coil.

Build the circuit to see what values you need.

Also will the TVS be able to dissipate the watts of the 120V (rms) drop through the alternating zener diodes?

TVS are rated for surge current, and without knowing the product family I would be guessing at the steady state watts it can handle.

By applying a few more filters(active[not obsolete],general purpose,SPST, and eliminating the 277Vcoils), I got it down to 2 choices.

But this brings up another question for the OP: why not just use a relay with a coil designed for 240V? Such a relay will definitely pull in at less than 240V, but not likely at 120V. On the other hand, as Randall has indicated, although it probably won't pull in at 120V, once pulled in to the closed position, it might well remain closed as low as 120V.

If you are trying to make an existing 120V relay only work at close to 240V, then there must be something in the circuit that either:

1. Wastes the same amount of energy as does the 120v coil. A simple resistor having the same resistance as the impedance of the relay coil, and physically large enough to handle the power, connected in series with the coil, would do the job.

2. Reduces the voltage by 120V, yet can carry sufficient current to reliably activate and hold the magnetic coil. A TVS that fires at 120V, as you showed, would theoretically reduce the voltage, without the resistor and capacitor, but I know nothing about the TVS current handling ability on a continuously repeated basis. That 1kΩ resistor will clearly prevent sufficient current. If you elect to experiment (which I highly recommend), please wear some form of eye protection. I presume you are aware that the capacitor must be a non-polarized type; an electrolytic would explode in short order.

You are apparently aware that the ON time will be shorter. Since the angle whose sine is 0.5 is 30°, the TVS wouldn't begin to conduct until one third of the way through the 90° rise time, assuming the the TVS triggers right at 120v, which is clearly NOT the case. Since the peak voltage of 120VRMS is around 160V, a 120V TVS must not fire until the voltage reaches well above 160V. I know nothing about the turn-off characteristics of a TVS as the voltage drops; once triggered, it may well continue to conduct well after the line voltage drops below 120V