mikeb
New Member
I need to change the characteristics of a light dimmer switch, such that I can control a light to be either 100% on or off, with no variable voltage.
The switch is a Lutron Maestro Dimmer/Fan Switch.
The model number is MA-LFQM. Its characteristics (from my tests below) led me to believe it is a solid state switch.
https://www.lutron.com/maestro/maestrofan.asp?s=17000&t=17200
(Installation instruction PDF can also be found on that page.)
I also own a ceiling fan with a non-dimmable fluorescent ballast. The solid state light dimming function of the Lutron switch will damage a non-dimmable fluorescent ballast over time, according to the fan manufacturer and Lutron.
The switch has a wall switch module and a "canopy module".
The canopy module exhibits a couple interesting properties:
Test 1: This test is conducted with an incandescent 60W bulb connected to the "light (hot)" wire from the canopy module.
Placing a voltmeter across AC neutral and AC hot from the canopy module shows a non 120V voltage. As a matter of fact, the 60W bulb shows about 30 Vac.
My theory: use a relay to turn on/off the fluorescent light.
My research led me to buy an Omron G2R-1-S-N General Purpose Relay. The data sheet can be found here:
http://oeiwcsnts1.omron.com/pdfcatal.nsf/0/FCB5B24C1940341986256FCE00764454/$file/D20G2RS0305.pdf
Initially, when I connected the relay, I observed these canopy properties:
Test 2: For this test, I connected the relay to the “light (hot)” wire from the canopy module.
Placing a voltmeter across AC neutral and AC hot from the canopy module through the relay, the meter showed about 2 Vac.
When I used the switch to change the dimmer from 100% to 50%, I observed the little LED dim, but this voltage is nowhere near enough to operate the relay’s coil.
This led me to believe that the canopy module is fairly smart, in this case maybe too smart.
Test 3: So, I connected an incandescent bulb in series with the relay. This combination failed to make the light illuminate, but the relay’s LED would dim, similar to test 2.
Test 4: Next, I connected the incandescent light in parallel with the relay coil. This combination is closer to what I desire.. When the dimmer is a 100%, the relay is tripped on, when the dimmer is at 0%, the dimmer is tripped off.
However, there is a problem using this relay. When the dimmer goes from 100% down to about 40%, the voltage drops from about 30 Vac to 15Vac. At 15Vac, the relay rapidly operates and releases the switched terminals. This rapid switching will kill a fluorescent ballast, which expects a constant voltage.
What do I need to add to this circuit to accomplish my original goal: When the dimmer is “on”, the fluorescent ballast is 100% on. When the dimmer is “off,” the fluorescent ballast is off. When the dimmer is in-between 100% and off, the fluorescent ballast must receive a constant voltage.
I have some electrical circuit knowledge and experience, I am good with solder, but I am in need of ideas for how to proceed from here.
I looked into undervoltage circuits, but they are too bulky to fit into a fan canopy or ceiling electrical box.
Any ideas or suggestions would be appreciated.
Regards,
--Mike
The switch is a Lutron Maestro Dimmer/Fan Switch.
The model number is MA-LFQM. Its characteristics (from my tests below) led me to believe it is a solid state switch.
https://www.lutron.com/maestro/maestrofan.asp?s=17000&t=17200
(Installation instruction PDF can also be found on that page.)
I also own a ceiling fan with a non-dimmable fluorescent ballast. The solid state light dimming function of the Lutron switch will damage a non-dimmable fluorescent ballast over time, according to the fan manufacturer and Lutron.
The switch has a wall switch module and a "canopy module".
The canopy module exhibits a couple interesting properties:
Test 1: This test is conducted with an incandescent 60W bulb connected to the "light (hot)" wire from the canopy module.
Placing a voltmeter across AC neutral and AC hot from the canopy module shows a non 120V voltage. As a matter of fact, the 60W bulb shows about 30 Vac.
My theory: use a relay to turn on/off the fluorescent light.
My research led me to buy an Omron G2R-1-S-N General Purpose Relay. The data sheet can be found here:
http://oeiwcsnts1.omron.com/pdfcatal.nsf/0/FCB5B24C1940341986256FCE00764454/$file/D20G2RS0305.pdf
Initially, when I connected the relay, I observed these canopy properties:
Test 2: For this test, I connected the relay to the “light (hot)” wire from the canopy module.
Placing a voltmeter across AC neutral and AC hot from the canopy module through the relay, the meter showed about 2 Vac.
When I used the switch to change the dimmer from 100% to 50%, I observed the little LED dim, but this voltage is nowhere near enough to operate the relay’s coil.
This led me to believe that the canopy module is fairly smart, in this case maybe too smart.
Test 3: So, I connected an incandescent bulb in series with the relay. This combination failed to make the light illuminate, but the relay’s LED would dim, similar to test 2.
Test 4: Next, I connected the incandescent light in parallel with the relay coil. This combination is closer to what I desire.. When the dimmer is a 100%, the relay is tripped on, when the dimmer is at 0%, the dimmer is tripped off.
However, there is a problem using this relay. When the dimmer goes from 100% down to about 40%, the voltage drops from about 30 Vac to 15Vac. At 15Vac, the relay rapidly operates and releases the switched terminals. This rapid switching will kill a fluorescent ballast, which expects a constant voltage.
What do I need to add to this circuit to accomplish my original goal: When the dimmer is “on”, the fluorescent ballast is 100% on. When the dimmer is “off,” the fluorescent ballast is off. When the dimmer is in-between 100% and off, the fluorescent ballast must receive a constant voltage.
I have some electrical circuit knowledge and experience, I am good with solder, but I am in need of ideas for how to proceed from here.
I looked into undervoltage circuits, but they are too bulky to fit into a fan canopy or ceiling electrical box.
Any ideas or suggestions would be appreciated.
Regards,
--Mike