wquiles
Flashaholic
I recently finished my own M6-R pack from the M6-R LVR3I PWM regulators and other components that js (Jim) made available for sale here .
As shown in those links, these regulators by Willie Hunt use PWM (Pulsed Width Modulation) and a varying duty cycle (percentage of ON vs. OFF cycles) to regulate the equivalent DC voltage that incandecent volts require for optimum performance, plus the soft start provided by Willie also helps in prolonging the life of the bulb as the inrush currents on a cold filament are much smaller, as shown here .
After building my own pack, I studied the schematics that Willie provided on his web site and concluded (at least initialy) that changing R4 "should" lower/raise the regulated output voltage.
I contacted Willie by email and he replied (thanks much Willie !!!) that indeed, changing R4 does what I expected, but that it also lower/raises the set voltage for the warning pulses from a depleted battery (also included in Willie's LVR regulator).
I tried measuring the RMS or DC equivalent voltage with several of my meters and with the built-in RMS voltage measurement on my high-end Tek scope, but none measured properly the approx. 6.8V output. I asked for help in measuring the RMS voltage, and Willie added that only the true high-end meters like Fluke Model 89 or 189 do measure true-RMS on the DC voltage scale. Basically, most meters (like my Fluke M87) only measure "average" voltage on the DC scale and true RMS on the AC scale, so the measure of the LVR's output will always be wrong (too low).
Following his instructions, I was able to measure the output voltage (which in fact was 6.8 volts!), and I therefore proceeded to plan making changes to R4.
I have been asking for Jim's help in driving the MN20 better with the LVRi that he got from Willie Hunt. With Jim's advice (V approx 7.5-6 volts), and Willies' information, after some simple math and after looking at available surface mount resistor values, I decided to try R4=54.9K ohms
Here is my always busy and over-spilling bench with the "patient" waiting its transplant:
Here are the very small resistors used: both 1/10Watt and 1/8Watt. The HUGE black thing is the black button cover of a M*g light!:
Here is the patient with the "chest" still open after the transplant - will it survive the operation?:
Here are the results with the 100Ohm load as Willie recommended - success !!!:
Here is the real test "load", a real MN15 bulb (no 100Ohm resistor like I used earlier to test/measure voltages as Willie suggested):
Here you can see the soft-start on the real bulb:
and here are the measured and calculated new DC or equivalent output, right at 7.4Volts!:
and here is the patient after recovery, driving an MN15 bulb - much whiter and much nicer than before!:
Since I have several contact points and wires, clippie things, etc., in series with the battery and the bulb, the measured 7.4V must really be around 7.5V or so, so I have met my initial goal for a regulated 7.5V LVR "transplant"
The only thing left to do is to do a couple of charge and run tests to verify the new slightly higher voltage setpoint for the warning flashes. I will report later once I have this data.
I hope this was helpful
Will
As shown in those links, these regulators by Willie Hunt use PWM (Pulsed Width Modulation) and a varying duty cycle (percentage of ON vs. OFF cycles) to regulate the equivalent DC voltage that incandecent volts require for optimum performance, plus the soft start provided by Willie also helps in prolonging the life of the bulb as the inrush currents on a cold filament are much smaller, as shown here .
After building my own pack, I studied the schematics that Willie provided on his web site and concluded (at least initialy) that changing R4 "should" lower/raise the regulated output voltage.
I contacted Willie by email and he replied (thanks much Willie !!!) that indeed, changing R4 does what I expected, but that it also lower/raises the set voltage for the warning pulses from a depleted battery (also included in Willie's LVR regulator).
I tried measuring the RMS or DC equivalent voltage with several of my meters and with the built-in RMS voltage measurement on my high-end Tek scope, but none measured properly the approx. 6.8V output. I asked for help in measuring the RMS voltage, and Willie added that only the true high-end meters like Fluke Model 89 or 189 do measure true-RMS on the DC voltage scale. Basically, most meters (like my Fluke M87) only measure "average" voltage on the DC scale and true RMS on the AC scale, so the measure of the LVR's output will always be wrong (too low).
Following his instructions, I was able to measure the output voltage (which in fact was 6.8 volts!), and I therefore proceeded to plan making changes to R4.
I have been asking for Jim's help in driving the MN20 better with the LVRi that he got from Willie Hunt. With Jim's advice (V approx 7.5-6 volts), and Willies' information, after some simple math and after looking at available surface mount resistor values, I decided to try R4=54.9K ohms
Here is my always busy and over-spilling bench with the "patient" waiting its transplant:
Here are the very small resistors used: both 1/10Watt and 1/8Watt. The HUGE black thing is the black button cover of a M*g light!:
Here is the patient with the "chest" still open after the transplant - will it survive the operation?:
Here are the results with the 100Ohm load as Willie recommended - success !!!:
Here is the real test "load", a real MN15 bulb (no 100Ohm resistor like I used earlier to test/measure voltages as Willie suggested):
Here you can see the soft-start on the real bulb:
and here are the measured and calculated new DC or equivalent output, right at 7.4Volts!:
and here is the patient after recovery, driving an MN15 bulb - much whiter and much nicer than before!:
Since I have several contact points and wires, clippie things, etc., in series with the battery and the bulb, the measured 7.4V must really be around 7.5V or so, so I have met my initial goal for a regulated 7.5V LVR "transplant"
The only thing left to do is to do a couple of charge and run tests to verify the new slightly higher voltage setpoint for the warning flashes. I will report later once I have this data.
I hope this was helpful
Will
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