Re: [CAD_CAM_EDM_DRO] CRAZY RELAY???

From: "ralaco" <ralaco@...>
Subject: [CAD_CAM_EDM_DRO] CRAZY RELAY???

> I installed a solid state Relay to control my Router with Mach1.
>
> When I connect the Router to the Relay nothing happen, but if I
> install a bulb with the Router, everything is OK, the Router and the
> bulb turns ON and OFF.
>
> Is this OK and why?

Some solid state relays don't work properly with inductive devices such as
motors. Adding a light bulb makes the load more resistive and lets the
solid state relay work.

>
> Is there a way, to make it works without a bulb

You could replace the light bulb with a resistor. Find out what the lowest
wattage bulb is that works. Assuming your line voltage is V and the bulb
wattage is P, you need a resistor with resistance of about R (ohms) = V^2 /
P. The power rating of the resistor should be V^2 / R (R is the resistance
value you buy). It's possible such a resistor won't work (because light
bulbs aren't exactly like resistors), so if it doesn't work, add a second
resistor of the same resistance and power in parallel with the first, and it
should work. Note, the resistors will get as hot or hotter than the light
bulb they replace.

You might be able to find a solid state relay that is intended to work with
motors.

A conventional (electro-mechanical) relay (with adequate contact current
rating) will work for sure without light bulbs, but you will probably need a
relay driver circuit to operate it.

The router will probably work with DC (rectified AC, no filter capacitors
needed), which means you could use a high voltage MOSFET to turn the router
on and off. But this involves working with line voltage and current, and
you **REALLY** need some isolation between the control signal and the high
voltage circuits, so don't proceed unless you know what you are doing.

Cheers,
- Jan

>
> Regards
> Raul Lara