Back in 2012, there was a conversation about cold ohm’s testing of lamps. Meaning testing the lamp’s filament by way of Ohm’s of resistance when the lamp is not running - just off/storage/in cold mode.
I was so hopeful in testing this theory for a problem, my staff and I tested well over a hundred new 1Kw PAR 64 lamps of many brands, but mostly the newest Generic China brand of lamps. Meter everything, see what we get..... starting to see a trend of most lamps reading between 1.25 and 1.05 Ohm’s, let’s segregate every lamp not within that range. This in addition to another important detail pointed out some other day for design issue with the newer PAR 64 lamps.
Back about than there was also a national Lighting Technicians Certification test of some sort. Believe there was a question on it about a HPL lamp ohm's reading.. Was it really just E/I=R? Volts devided by Amps = Ohms of resistance, or was it a different formula more useful for lamps that one cannot test anyway unless operating.... and at that point the Amps is easier to measure in... 8.333+ equals 1Kw.
silicsound Oct 3, 2012
“If you try and use ohms law to find the resistance of each lamp wattage, you will find that the resistance will be around 20 times less in practice since the lamp is cold. As far as the condition goes, resistance should increase with age.”
Per Osram “Tungsten Halogen Low Votage Lamps Photo Optics” c.2000, (the manual on lamps - and should have a link somewhere on the CB website.) Yes, used lamps will have a decimal of in the Hundred’s in factor for properly operating halogen lamps for Ohm’s reading. For the most part a properly operating halogen cycle will by ETC Sensor dimmer rack with buffering for current and warming adjustment if properly adjusted, age of lamp will have very little noticeable Ohm’s difference in a lamp.. Found no real differences in testing some used lamps also.
In addition to Friday’s tested lamps, I just Ohm’s metered out well over a hundred 1Kw PAR 64 lamps of multiple brands today - mostly the discontinued name brands GE and Osram, and a few of the Keller Williams holdover GE lamps - post GE discontinuing the lamp & while in Mexico filament change before China. This was including some used lamps.
All were tested with a Extech #EX530 meter. My readings given probes instead of clamp jaws (Fluke clamp jaws were tried without any better results.) Were widely ranging in all brands of lamp, but the (Cold Norm) seemed to be mostly in the 1.27 - 0.99 range with a lot of outliers. Ohm’s readings were at times in the 2.6 Ohm range, at times much larger, and at times the meter could not range to a set reading. I believe this much to contact with the probe and or the weld of the lamp’s ferrule (pins) to the GX-16d prongs.
It can be safely said that even though there is differences in beam spread, there is no ohm’s cold difference between a VNSP and WFL 1Kw PAR 64 lamp - a question I wanted to confirm.
A sampling of today’s testing of new lamps:
GE - FFN:
1.00, 0.96, 0.98, 1.15, 1.01, 1.18.
Generic Keller Williams (Mexico) w. GE markings - FFN:
3.16, 1.34, 1.68, 0.99, 1.28, 1.09, 1.77, 1.13, 1.24, 1.37, 2.52, 1.84, 1.01, 1.41, 1.09, 1.02, 1.07, 1.39.
GE - FFS:
1.13, 1.19, 0.98, 0.97, 1.24, 2.12, 0.99, 1.21, 1.95, 1.07, 1.31, 1.06, 1.37, 1.07, 1.04, 1.00, 1.01, 1.24, 1.20, 1.02, 1.09, 2.64, 1.00, 1.00, 1.06, 1.13, 1.02, 1.47, 2.25, 1.02.
Osram - FFS:
12.30, 2.33, 1.39, 1.20, 2.39, Bad, 2.24, 1.17, 1.18, 1.53, 26.17
GE - FFS:
1.28, 1.10, 2.52, 1.62, 1.22, 1.06, 1.07, 1.02, 1.00, 1.04, 1.07, 0.99 1.15, 1.02, 1.00, 1.04, 1.07, 0.99, 1.15, 1.07, Bad, 1.68, 1.00 (used), 1.76, 1.31, 1.13, 1.63, 1.09, 1.11, 1.10
Generic Keller Williams (China?) Without GE Markings and same otherwise as Generic China Brand. Vertical instead of horizontal filament noted for this lamp also:
1.20, 1.21, 1.22, 1.27, 1.24, 1.20. Ohms’ Resistance per Cold lamp.
The rest of the (China) lamps tested I don’t have my notes at home on, but I would say 90% of them in the Generic China only brand - without the Keller Williams branding (on the outer case) are within a range of 1.25-1.05 Ohms resistance. The last 10% are similar in out of norm, Really odd resistance, or over 1.30 range for cold resistance. Could almost say, in cold Ohm’s metering... the new China Generic PAR 64 lamps are on average while cool testing more in the above normal range than the percentage of GE or Osram lamps.
Did a quick check of some used 750w Philips #7981P and many brands of used 500w BTL lamps in cold Ohm’s testing:
#7981P
1.21, 1.26, 1.60, 1.86, 1.56, 1.85, 1.36, 1.40, 1.23, 1.69
BTL
Only 5 of 8 BTL lamps tested would provide a stable reading (as found on some or high Ohm’s PAR 64 lamps amongst brands at times.)
2.01, 2.02, 1.90, 1.94, 1.94 ohms.
So... cold lamp ohm’s testing of lamps in general does not have any relevance other than perhaps if you get a good reading... a 750w/115v #6981P lamp perhaps is in the 1.5 range of ohms resistance average? Yet the 500w/120v BTL lamp is in the 1.23 Ohm range. In other words, cold Ohm’s testing it would seem is no real measurement of a cold lamp’s actual working resistance to current flow by way of wattage. Or even much so far without running the out-liers in testing if an indication of quick failure.
Amperage testing of an operating lamp shows some promiss. This especially with outlier lamps. Testing will require new lamp sockets to all fixtures to test in adding to the physical testing. Amongst other details.
1Kw PAR 64 lamps of today's Generic China version.... something in study. The lamp captule change on the fixtures I see, TBA for research and complience specifications.
I was so hopeful in testing this theory for a problem, my staff and I tested well over a hundred new 1Kw PAR 64 lamps of many brands, but mostly the newest Generic China brand of lamps. Meter everything, see what we get..... starting to see a trend of most lamps reading between 1.25 and 1.05 Ohm’s, let’s segregate every lamp not within that range. This in addition to another important detail pointed out some other day for design issue with the newer PAR 64 lamps.
Back about than there was also a national Lighting Technicians Certification test of some sort. Believe there was a question on it about a HPL lamp ohm's reading.. Was it really just E/I=R? Volts devided by Amps = Ohms of resistance, or was it a different formula more useful for lamps that one cannot test anyway unless operating.... and at that point the Amps is easier to measure in... 8.333+ equals 1Kw.
silicsound Oct 3, 2012
“If you try and use ohms law to find the resistance of each lamp wattage, you will find that the resistance will be around 20 times less in practice since the lamp is cold. As far as the condition goes, resistance should increase with age.”
Per Osram “Tungsten Halogen Low Votage Lamps Photo Optics” c.2000, (the manual on lamps - and should have a link somewhere on the CB website.) Yes, used lamps will have a decimal of in the Hundred’s in factor for properly operating halogen lamps for Ohm’s reading. For the most part a properly operating halogen cycle will by ETC Sensor dimmer rack with buffering for current and warming adjustment if properly adjusted, age of lamp will have very little noticeable Ohm’s difference in a lamp.. Found no real differences in testing some used lamps also.
In addition to Friday’s tested lamps, I just Ohm’s metered out well over a hundred 1Kw PAR 64 lamps of multiple brands today - mostly the discontinued name brands GE and Osram, and a few of the Keller Williams holdover GE lamps - post GE discontinuing the lamp & while in Mexico filament change before China. This was including some used lamps.
All were tested with a Extech #EX530 meter. My readings given probes instead of clamp jaws (Fluke clamp jaws were tried without any better results.) Were widely ranging in all brands of lamp, but the (Cold Norm) seemed to be mostly in the 1.27 - 0.99 range with a lot of outliers. Ohm’s readings were at times in the 2.6 Ohm range, at times much larger, and at times the meter could not range to a set reading. I believe this much to contact with the probe and or the weld of the lamp’s ferrule (pins) to the GX-16d prongs.
It can be safely said that even though there is differences in beam spread, there is no ohm’s cold difference between a VNSP and WFL 1Kw PAR 64 lamp - a question I wanted to confirm.
A sampling of today’s testing of new lamps:
GE - FFN:
1.00, 0.96, 0.98, 1.15, 1.01, 1.18.
Generic Keller Williams (Mexico) w. GE markings - FFN:
3.16, 1.34, 1.68, 0.99, 1.28, 1.09, 1.77, 1.13, 1.24, 1.37, 2.52, 1.84, 1.01, 1.41, 1.09, 1.02, 1.07, 1.39.
GE - FFS:
1.13, 1.19, 0.98, 0.97, 1.24, 2.12, 0.99, 1.21, 1.95, 1.07, 1.31, 1.06, 1.37, 1.07, 1.04, 1.00, 1.01, 1.24, 1.20, 1.02, 1.09, 2.64, 1.00, 1.00, 1.06, 1.13, 1.02, 1.47, 2.25, 1.02.
Osram - FFS:
12.30, 2.33, 1.39, 1.20, 2.39, Bad, 2.24, 1.17, 1.18, 1.53, 26.17
GE - FFS:
1.28, 1.10, 2.52, 1.62, 1.22, 1.06, 1.07, 1.02, 1.00, 1.04, 1.07, 0.99 1.15, 1.02, 1.00, 1.04, 1.07, 0.99, 1.15, 1.07, Bad, 1.68, 1.00 (used), 1.76, 1.31, 1.13, 1.63, 1.09, 1.11, 1.10
Generic Keller Williams (China?) Without GE Markings and same otherwise as Generic China Brand. Vertical instead of horizontal filament noted for this lamp also:
1.20, 1.21, 1.22, 1.27, 1.24, 1.20. Ohms’ Resistance per Cold lamp.
The rest of the (China) lamps tested I don’t have my notes at home on, but I would say 90% of them in the Generic China only brand - without the Keller Williams branding (on the outer case) are within a range of 1.25-1.05 Ohms resistance. The last 10% are similar in out of norm, Really odd resistance, or over 1.30 range for cold resistance. Could almost say, in cold Ohm’s metering... the new China Generic PAR 64 lamps are on average while cool testing more in the above normal range than the percentage of GE or Osram lamps.
Did a quick check of some used 750w Philips #7981P and many brands of used 500w BTL lamps in cold Ohm’s testing:
#7981P
1.21, 1.26, 1.60, 1.86, 1.56, 1.85, 1.36, 1.40, 1.23, 1.69
BTL
Only 5 of 8 BTL lamps tested would provide a stable reading (as found on some or high Ohm’s PAR 64 lamps amongst brands at times.)
2.01, 2.02, 1.90, 1.94, 1.94 ohms.
So... cold lamp ohm’s testing of lamps in general does not have any relevance other than perhaps if you get a good reading... a 750w/115v #6981P lamp perhaps is in the 1.5 range of ohms resistance average? Yet the 500w/120v BTL lamp is in the 1.23 Ohm range. In other words, cold Ohm’s testing it would seem is no real measurement of a cold lamp’s actual working resistance to current flow by way of wattage. Or even much so far without running the out-liers in testing if an indication of quick failure.
Amperage testing of an operating lamp shows some promiss. This especially with outlier lamps. Testing will require new lamp sockets to all fixtures to test in adding to the physical testing. Amongst other details.
1Kw PAR 64 lamps of today's Generic China version.... something in study. The lamp captule change on the fixtures I see, TBA for research and complience specifications.