Zellarman Posted August 14, 2009 Share Posted August 14, 2009 Well, I'm soon to be ony my third in-line relay controlling a bathroom exhaust fan. The first one lasted quite a while compared to the 3 months for the second one. They're supposed to be good for up to 15 A inductive loads, and the fan is nowhere near 15 Amps, so what could be going wrong? Smarthome today said perhaps there's not enough of a load. Without adding an additional device to the load of the relay is there any safe way to increase the load, perhaps a resistor parallel to the fan? Though I've gotta say doing something like this kind of makes me wary of a fire. Has anyone experienced difficulties w/ an in line relay controlling an inductive load? Link to comment Share on other sites More sharing options...
ResIpsa Posted August 14, 2009 Share Posted August 14, 2009 FWIW, I use an inline relay to control an outdoor outlet that is primarily used for holiday lighting. The load is probably no more than 5 or 6 amps, and I have had a 100% success rate with it. Good luck. Link to comment Share on other sites More sharing options...
ergodic Posted August 14, 2009 Share Posted August 14, 2009 I'm using two to control exhaust fan/light units with no problem (after a few months so maybe I just have to wait ) One is an inline and the other is an SL relay - I think except for packaging they're essentially the same. Very possibly your particular fan is generating an on/off backtransient that's causing the unit to break down and fail. A nonpolarized shunt capacitor could solve that easily but you'd need to scope it to really see what's going on and what fixes it - could be easier on your life to just try a different fan unit. Also, the relays don't generate a lot of heat, but inside a box they still can get pretty well warmed up - if you haven't I'd try drilling some additional ventilation. It may just partly be a thermal breakdown problem over time. Aside from the fact that it's not likely to solve any problem, under no circumstances would I advise any sort of resistor anywhere in that circuit. Link to comment Share on other sites More sharing options...
SteveL Posted August 15, 2009 Share Posted August 15, 2009 I think Smarthomes comment of adding load go to an old problem where a switch without any load would put more heat on the internal components than a switch that had a load attached to it. The load would draw the heat away from the switch. Steve L Smarthome Link to comment Share on other sites More sharing options...
Brian H Posted August 15, 2009 Share Posted August 15, 2009 SteveL. I have been an electronic technician for over 50 years. I have never seen a load keep a switch cooler. Smarthome must really have some unique designs. Link to comment Share on other sites More sharing options...
SteveL Posted August 16, 2009 Share Posted August 16, 2009 Not the overall temp of the switch but specific parts like diodes or a single resistor. Steve L Smartlabs / Smarthome Link to comment Share on other sites More sharing options...
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