DIY: How to get a 175w MH ballast and Mogul socket for under $50!..pic heavy
- Thread starter Corndork2
- Start date
PaulErik
Premium Member
The lamp in the test picture looks to be a mercury vapor lamp because the arc length is too long for it to be a 175-watt metal halide lamp. GE does not manufacture a 6500K MH lamp.
The ballast inside the Regent and other brand 175-watt MV security lights are a normal power factor high reactance autotransformer (HX-NPF) ANSI H39 mercury vapor ballast. These are not even close electrically to an ANSI M57 metal halide ballast. The HX-NPF ballast is commonly used in these mercury vapor lights because of size and cost of materials to manufacture them.
Mercury vapor ballasts (constant wattage autotransformer CWA and high reactance HX) are considered electrically not compatible with metal halide lamps. The open circuit voltage (OCV) for a 175-watt mercury vapor ANSI H39 HX ballast is too low to reliably start/ignite ANSI M57 spec 175-watt metal halide lamps.
Generally almost all ANSI M57 ballasts are CWA type and always have a high power factor because of the capacitor. The capacitor in this type of system is used only for lamp regulation and power factor correction. The ballast coil voltage is peaked for lamp starting. CWA mercury vapor ballasts use the capacitor for peaking the OCV to start the lamp. Metal halide lamps are not compatible with peaking capacitor systems but this does not apply to this thread.
Usually if you use a metal halide (ANSI M57 spec) lamp on any mercury ballast circuit the lamp will have difficulty starting and staying lit during the warm up phase. The arc usually becomes unstable and the ballast can not support the electrical discharge. This may not be a problem at first but will become apparent once the lamp ages. The mercury ballast has a higher secondary short circuit current and lower OCV than metal halide lamps are designed for. Another difference is the current crest factor (CCF). Mercury vapor lamps can a handle a higher CCF than metal halide lamps. If a lamp is operated with a higher CCF than the maximum rating the lamp will wear out quickly (excessive electrode wear).
Mercury Vapor ANSI H39 Ballast Specification
Open Circuit Voltage: 225-255OCV
Secondary Short Circuit Current: 2.0-3.6A
Current Crest Factor: 2.0CCF Max
Metal Halide ANSI M57 Ballast Specification
Open Circuit Voltage: 285-320OCV
Secondary Short Circuit Current: 1.5-1.9A
Current Crest Factor: 1.8CCF Max
The specifications listed above are general ballast ANSI (American National Standards Institute) standards manufacturers follow.
However mercury vapor lamps are compatible with probe start metal halide ballasts of the same wattage. This is why most probe start metal halide ballasts are rated and labeled for metal halide and mercury vapor (example: ANSI M57/H39).
The ballast inside the Regent and other brand 175-watt MV security lights are a normal power factor high reactance autotransformer (HX-NPF) ANSI H39 mercury vapor ballast. These are not even close electrically to an ANSI M57 metal halide ballast. The HX-NPF ballast is commonly used in these mercury vapor lights because of size and cost of materials to manufacture them.
Mercury vapor ballasts (constant wattage autotransformer CWA and high reactance HX) are considered electrically not compatible with metal halide lamps. The open circuit voltage (OCV) for a 175-watt mercury vapor ANSI H39 HX ballast is too low to reliably start/ignite ANSI M57 spec 175-watt metal halide lamps.
Generally almost all ANSI M57 ballasts are CWA type and always have a high power factor because of the capacitor. The capacitor in this type of system is used only for lamp regulation and power factor correction. The ballast coil voltage is peaked for lamp starting. CWA mercury vapor ballasts use the capacitor for peaking the OCV to start the lamp. Metal halide lamps are not compatible with peaking capacitor systems but this does not apply to this thread.
Usually if you use a metal halide (ANSI M57 spec) lamp on any mercury ballast circuit the lamp will have difficulty starting and staying lit during the warm up phase. The arc usually becomes unstable and the ballast can not support the electrical discharge. This may not be a problem at first but will become apparent once the lamp ages. The mercury ballast has a higher secondary short circuit current and lower OCV than metal halide lamps are designed for. Another difference is the current crest factor (CCF). Mercury vapor lamps can a handle a higher CCF than metal halide lamps. If a lamp is operated with a higher CCF than the maximum rating the lamp will wear out quickly (excessive electrode wear).
Mercury Vapor ANSI H39 Ballast Specification
Open Circuit Voltage: 225-255OCV
Secondary Short Circuit Current: 2.0-3.6A
Current Crest Factor: 2.0CCF Max
Metal Halide ANSI M57 Ballast Specification
Open Circuit Voltage: 285-320OCV
Secondary Short Circuit Current: 1.5-1.9A
Current Crest Factor: 1.8CCF Max
The specifications listed above are general ballast ANSI (American National Standards Institute) standards manufacturers follow.
However mercury vapor lamps are compatible with probe start metal halide ballasts of the same wattage. This is why most probe start metal halide ballasts are rated and labeled for metal halide and mercury vapor (example: ANSI M57/H39).
Wrassemeister
New member
well that is an easier explanation 
rustybucket145
New member
Much better! I was getting crosseyed there for a minute 
On someone's question on the enclosure for the ballast. I used a Military Metal Ammo box i had sitting around. works great!
I bought my MH ballasts at the Local Electrical supply house for roughly $50/ea DIY'd a Lumenarc type reflector and used the ammo box to house the ballasts. All in all after bulb purchase and wiring supplies I ended up with a pretty slick lighting setup for under $150. By no means is it free or cheap, but it's much better than paying full price for a fixture, and you learn a little in the process
On someone's question on the enclosure for the ballast. I used a Military Metal Ammo box i had sitting around. works great!
I bought my MH ballasts at the Local Electrical supply house for roughly $50/ea DIY'd a Lumenarc type reflector and used the ammo box to house the ballasts. All in all after bulb purchase and wiring supplies I ended up with a pretty slick lighting setup for under $150. By no means is it free or cheap, but it's much better than paying full price for a fixture, and you learn a little in the process
cannarella
New member
PaulErik do you do lighitng specifications for building projects?
Corndork2
New member
I have used this ballast to sucessfully fire two or three different kinds of bulbs. I also ran them for over 3 months. They did have a harder time initiallt striking their arc, probaly because there is no cap, but they did work fine, and work for as long as I needed them before I tore my setup down.
cannarella
New member
3 months is fine but who has been running them for 3+ years? If it is not designed for a MH lamp I would hesitant to use it. You can find used multi-tap real MH ballasts with capacitors and a mogul socket for the price you paid for that fixture and they will work reliably for years.
AquariaOCD
New member
If the ballast is the same, and the only difference is the capacitor, the obvious constructive question in MY feeble mind would be "where to get the capacitor and how to wire it in?" instead of debating the fact of what is going to happen to the bulbs in the long run without it.
Corndork, could we get a good pic of the label on the ballast? I think you are off to a good start!
Corndork, could we get a good pic of the label on the ballast? I think you are off to a good start!
AquariaOCD
New member
double post
Last edited:
cannarella
New member
Look on clubs web sites. I have about 10 175W MH ballasts and new mogul sockets that I usually let go for under $30. Be resourceful. I saw a 400W MH ballast new on Ebay for $10.
cannarella
New member
No problem. Good luck.
peregrinus
New member
I did this same thing about 2 years ago. bought 4 of those setups and gutted them. i used a 20 k bulb in one of them as a test. and all worked fine for a month or so and after that it would not fireup the bulb but i put th MV bulb back in and it worked fine also the 20k bulb in MH worked fine. do you think the ballest would not fire it any more because it weakened it?
peregrinus
New member
also i used an old computer case for the encoluser.. worked great..
wooden_reefer
New member
I think the magnetic ballast is not energy efficient.
May be an obsolete technology.
Does an electronic ballast save 5 cents a day?
May be an obsolete technology.
Does an electronic ballast save 5 cents a day?
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