It depends what your blower's on/off sequence is. If its a simple power switch, I assume you could just use a relay to toggle the power on and off with your timer.
Yes you can switch contactor induction coil with simple switch or some control circuits. When you switch off coil of contactor all three and null on contactor is turned off, this depends from contactor which you are using, some contactors have different ports state from others. This induction coil is monophase and switch is simple.
In my post #8 you see three contactors, third on right of picture can be used for three phase system switching. Controling of contactor switch off/on is done over A1 and A2 ports on it. On A1 is connected phase (one) and on A2 is connected null. In other words A1 and A2 represent coil of contactor like at relays, but this coil working on 220V. Also there is contactors with coils on 12V, 24V, 48V,...
You can use any control circuit what you whish. Here is my example of switching timer device :
I use mono phase mains outlet, if I need I can just replace that outlet with three phase and I can control three phase device. Timer is used to switch on some deivces each day at preset time, you can use any control circuit what you need.
where is electromechanical off delay timers in these two pictures ?
I just wished to see the schematic ....... where the wires should be connected at the off delay timer .......... NO contacts would be used or NC contacts would be used ......... in order that the contactor just switched on or off whatever else want to achieve in the example ?