Question about mechanical relay

[martintorres]

Flfl m Sorry, I do not want to contradict your idea, but in my opinion, aside these simple solutions to control inductive loads triac; And you pose, if not understood why my English is half bad, not see obsolete.
The implementation of an auto-inductor in series with the triac and load respectively, is the appropriate solution, but given the size of the engine and do not know what experience does the friend, we recommend you implement contactors to start or stop the engine.
This would be an example of an auto-inductor:

The contactor coil can have 12 to 24-48cc / 110-220AC; For the case of implementing a contactor with AC coil, to my way of seeing things, the right thing would be to implement an opto-triac firing as auxiliary a triac, with the triac, the contactor coil excite ...
I leave as an example a development arm for the company forces (economic heating fuel) two years ago ...
Basically it is a simple fan controller, where the temperature program and then as sensing, turns on the fan to move the hot air on heating ducts.

Notes on the triac, there is a legend that says: "100uH", there, the auto-inductance is housed with their respective toroid
There are other specific integrated circuit solutions and ideal for these applications. For example IR21362, but is discontinued in the market, and has its complexity using this IC.
Years ago I dedicated to teaching and electronic developments, and the solution of the self-inductance was as simple and practical to implement ocurriopara I always control my projects ...