Does anyone have a used 175w DE MH laying around

[Jan]

I need to test a light fixture that uses 175Watt DE MH bulb to see if the bulb is burnt out or if the ballast is bad. I don't want to keep the bulb, just borrow it.

[zygote2k]

get a multimeter instead.

[Coral Hind]

get a multimeter instead.

 

How would she use the multimeter? More info might help her out if you have experience troubleshooting with a multimeter.

[zygote2k]

How would she use the multimeter? More info might help her out if you have experience troubleshooting with a multimeter.

 

I believe you would set it to "watts", then place each electrode on each end of the receptacle. If it reads drastically less, you might have a problem.

Origami is the electric man- ask him for clarity. I might get you electrocuted.

[Origami]

Jan, I think you're diagnostic method is the most straightforward path to take. Our bulbs often don't burn out, though, as spectrum shifts often occur much earlier and render the bulb unusable in our hobby. However, it's not beyond the possibility that you had a bad bulb. If you don't mind my asking, how long was the bulb in service? I wish I had a bulb for you but the only DE's I have are 150's and 250's.

 

A multimeter really won't do you much good here unless you suspected that there might be a problem with the wiring in the fixture. (A multimeter can give you rms volts, rms amps, and continuity - or resistance - measurements typically.)

[lanman]

I believe you would set it to "watts", then place each electrode on each end of the receptacle. If it reads drastically less, you might have a problem.

Origami is the electric man- ask him for clarity. I might get you electrocuted.

 

 

Pooof!! Hmm.... meter smells kind of funny.

 

You could read volts, if you knew how many volts you were expecting - but don't those things send out a 'spike' to start running? Or maybe that's only fluorescent light ballasts. You could read current - but you need a load (light bulb) in the circuit - and the meter between the load and the line; hard to rig up.

 

Best bet with a meter (IF you know how much voltage you're looking for) is to leave the light bulb in - and check the voltage across it. Start on a very high voltage setting on the meter - 10,000 volts oughta do it. Then switch down to 1000, and 500 if the reading is 110V, like I think it would be.

 

We are talking high-voltage, relatively high-current devices - I don't think I wanna stick my Simpson in there unless I have to. I like the light bulb idea.

 

bob

Edited September 16, 2009 by lanman

[Origami]

Metal halide bulbs (like fluorescent bulbs) are so-called "negative resistance" loads. They are therefore driven by constant current and not a constant voltage. The nominal operating current into a 175W single-ended bulb is 1.5 Amps and has a starting voltage of somewhere around 4000 volts (between 3500 and 6000 volts). However, when operating properly, the bulb should have a nominal operating voltage of around 132 volts across it. If it's not operating properly, the ballast may not put anything across it or it may put as much as 200 volts across the leads. It may depend on the ballast design.

 

Now, Jan, I can't seem to find many references to a 175W double ended lamp. Just 70/75, 150, 250 & 400W lamps are referenced in the several papers that I keep on the subject. I wonder if you could take a look at page 2 of this Ushio data sheet and tell me if your bulb conforms to the 150W or 250W lamp mechanical drawings? http://www.ushio.com/files/specs/Aqualite.pdf take a look at the connectors especially.

 

Also, what make/model ballast are you using?

Edited September 16, 2009 by Origami2547

[Coral Hind]

Tom, I talked to Jan yesterday on the phone and after some searching I was able to find some 175w DE bulbs. I suggested to her as a simple troubleshooting method that she should try to find a spare bulb instead of just ordering one as the problem maybe in the ballast which promted this post. Here is one of the sites I found that offers the bulb. http://www.lightspectrumstore.com/servlet/...lbs-Lamp/Detail

 

From personal experience of bench testing ballasts the average starting voltage on a "probe" start MH from the 175w to 400w are around 950v - 1100v. The "pulse" start as you mentioned was about 4 times that. The operating voltage drop of a 175w and 250w probe CWA was 60-70v, that was after an hour of burn time.

[Origami]

Tom, I talked to Jan yesterday on the phone and after some searching I was able to find some 175w DE bulbs. I suggested to her as a simple troubleshooting method that she should try to find a spare bulb instead of just ordering one as the problem maybe in the ballast which promted this post. Here is one of the sites I found that offers the bulb. http://www.lightspectrumstore.com/servlet/...lbs-Lamp/Detail

 

From personal experience of bench testing ballasts the average starting voltage on a "probe" start MH from the 175w to 400w are around 950v - 1100v. The "pulse" start as you mentioned was about 4 times that. The operating voltage drop of a 175w and 250w probe CWA was 60-70v, that was after an hour of burn time.

 

Thanks. It looks a lot like a 150W lamp in terms of the shape. I wonder if it fits in a 150W socket.

 

Since I could not find technical specs on a 175W DE MH bulb or ballast, I looked up one other similar bulb based on your link and found that, at least in one case, are billed as replacements for Coral Vue / Hamilton bulbs running on an M81 ballast. The thing is, the M81 is a pulse start 150W HQI ballast that's not a CWA (constant wattage auto-transformer) but HX-HPF (high reactance - high power factor) circuit. Also, neither Coral Vue's and Hamilton's websites list 175W DE products, just the standard wattages that were listed earlier. That (along with the facts of the ballast and the form factor) makes me wonder if these 175W DE lamps are really just 150W lamps. (That's why I asked about the make and model of the ballast - I was hoping it would tell me more about what it's actual driving parameters are.) There's so much variability in the actual power consumption of bulbs depending upon the ballast / bulb combination that it wouldn't surprise me at all if this were the case since many "150W" lamps draw 1.8 Amps at around 100Vrms when settled.

 

If it is the case, Jan should be able to take an old 150W DE bulb and do the test. In that case, I have a 150W bulb I could give her for the test. As long as the starting and operational parameters are compatible, the test should go fine and give her the answer she's looking for.

 

Jan, I've got a 150W bulb if you need it. There may be others closer to you with a 150W DE bulb, too, since they're not uncommon. Let me know if I can be of service.

[Jan]

Thank you Tom. I don;t have the light fixture. It's a fixture that i would like to purchase from someone for my pico. The guy that's selling the light said that the coralife 150w bulb that he has in it now was working last week. The unit is an Odyssey light fixure w/175w DE MH w/2pc's and moonlight LED's. We're trying to figure out if the problem is in the bulb or the ballast and that's how it got to this point.

 

I've forwarded your q's to the seller for answers. He's only about 10 minuts from me so I thought it would be easier to show up with a 175 watt bulb and test it out. As soon as he gets back to me with answers to your q's I'll get back to you. Thanks so much!

 

Thanks. It looks a lot like a 150W lamp in terms of the shape. I wonder if it fits in a 150W socket.

 

Since I could not find technical specs on a 175W DE MH bulb or ballast, I looked up one other similar bulb based on your link and found that, at least in one case, are billed as replacements for Coral Vue / Hamilton bulbs running on an M81 ballast. The thing is, the M81 is a pulse start 150W HQI ballast that's not a CWA (constant wattage auto-transformer) but HX-HPF (high reactance - high power factor) circuit. Also, neither Coral Vue's and Hamilton's websites list 175W DE products, just the standard wattages that were listed earlier. That (along with the facts of the ballast and the form factor) makes me wonder if these 175W DE lamps are really just 150W lamps. (That's why I asked about the make and model of the ballast - I was hoping it would tell me more about what it's actual driving parameters are.) There's so much variability in the actual power consumption of bulbs depending upon the ballast / bulb combination that it wouldn't surprise me at all if this were the case since many "150W" lamps draw 1.8 Amps at around 100Vrms when settled.

 

If it is the case, Jan should be able to take an old 150W DE bulb and do the test. In that case, I have a 150W bulb I could give her for the test. As long as the starting and operational parameters are compatible, the test should go fine and give her the answer she's looking for.

 

Jan, I've got a 150W bulb if you need it. There may be others closer to you with a 150W DE bulb, too, since they're not uncommon. Let me know if I can be of service.

[Jan]

It looks like a 150w bulb

 

Ballast info

 

 

 

 

Metal halide bulbs (like fluorescent bulbs) are so-called "negative resistance" loads. They are therefore driven by constant current and not a constant voltage. The nominal operating current into a 175W single-ended bulb is 1.5 Amps and has a starting voltage of somewhere around 4000 volts (between 3500 and 6000 volts). However, when operating properly, the bulb should have a nominal operating voltage of around 132 volts across it. If it's not operating properly, the ballast may not put anything across it or it may put as much as 200 volts across the leads. It may depend on the ballast design.

 

Now, Jan, I can't seem to find many references to a 175W double ended lamp. Just 70/75, 150, 250 & 400W lamps are referenced in the several papers that I keep on the subject. I wonder if you could take a look at page 2 of this Ushio data sheet and tell me if your bulb conforms to the 150W or 250W lamp mechanical drawings? http://www.ushio.com/files/specs/Aqualite.pdf take a look at the connectors especially.

 

Also, what make/model ballast are you using?

Edited September 17, 2009 by Jan

[Origami]

Jan, I'd go ahead and put a 150W bulb in circuit and test it that way. The circuit diagram on the side of the ballast that, if it's wired up this way, it's an HX-HPF circuit and includes a pulse ignitor (that's the HJM103 shown). With a working pulse ignitor, it should be able to fire up the bulb.

[Coral Hind]

Jan, I agree with Tom that it is safe to go with the 150w bulb. The ignitor pictured is labeled for a 150w bulb. The capacitor shown is also 16 Mfd which is what is normally with an M81 ballast. A 175w setup uses a 17 to 20Mfd capacitor.

Edited September 17, 2009 by Coral Hind