Checking Ballast Output on a HID Fixture

[Little Bill]

I found a chart that I have that says "Troubleshooting" at the top then it says" Open-Circuit Voltage Test Limits"

Then it has all the ballasts types, ie:mercury, metal halide, HP Sodium, Low Pressure Sodium.
Within each ballast type there is Wattage - ANSI number - RMS Voltage

Now I don't remember why I have this or where I got it but is it for checking output on HID ballasts?
If so that's what I need.

Let's say you have a MH ballast (M59) and the lamp is 400W and the RMS voltage listed is 225-255, does that mean you should have that voltage output from the ballast?

I don't understand, if it means the output voltage wouldn't you also need the line voltage supplying the ballast to be in the chart? Example: if the line voltage was 277V, that's already higher than the 225-255V listed in the chart.

Also, where would you take the measurement from to test this? Would you first remove the lamp then check between the contact in the base and neutral/shell of the socket? Or better I suppose, test the leads to the socket?

I just need a way to determine if only the lamp needs replacing or the ballast kit, or both.

 

[ActionDave]

Unless it is a regular customer I change the lamp and the ballast. I've been burned too many times by changing just the lamp and then the ballast goes out in less than a month or two.

 

[Little Bill]

Unless it is a regular customer I change the lamp and the ballast. I've been burned too many times by changing just the lamp and then the ballast goes out in less than a month or two.

It is a regular customer. He wants me to make sure that the ballast needs replacing instead of throwing it all in there. (His words)
I explained that even if the ballast shows good it may not last long if only the lamp is changed. Also would be another service call to come back. He's willing to take that chance.

I am going to probably change from probe start to pulse start now and try to talk him into LED wall pack for the next time they go out.

 

[ActionDave]

I know they make a HID tester tool but I have never used one.

 

[iwire]

The open circuit voltage is easily checked by unscrewing the lamp and using your meter to check the voltage between the screw shell and the center prong.

And yes this voltage often is below the fixture input voltage. That is the ballast doing its job.

 

[JFletcher]

I don't understand, if it means the output voltage wouldn't you also need the line voltage supplying the ballast to be in the chart? Example: if the line voltage was 277V, that's already higher than the 225-255V listed in the chart.

You wouldnt because each voltage has its own tap from the ballast. They will all be stepped up/down to roughly the same output voltage by the ballast.

Also, where would you take the measurement from to test this? Would you first remove the lamp then check between the contact in the base and neutral/shell of the socket? Or better I suppose, test the leads to the socket?

Test leads to the socket would be better tho that doesnt eliminate the socket itself as the failure point. and testing the ballast will not eliminate the possibility of the igniter or capacitor being toast.

The way Ive done it in the past is replace the bulb with a known good bulb first; if it works, let it go. If it doesnt, then check input voltage and if that's good, the guts get replaced.

 

[Cow]

I regularly test for open circuit test voltage when working on hids. If you have proper voltage in the socket but the bulb still doesn't light up check the cap. If the cap checks out, then you most likely have an issue with the socket.

I had this issue on the last 400w MH flood I worked on. Tested the socket, tested the cap, but the bulb still didn't light up. I went to unscrew the bulb out of the socket and must of found the sweet spot in the socket where it made a good connection and the bulb lit up.

I make a copy of that open circuit voltage table and give it to all the new guys for troubleshooting.

 

[tom baker]

You can use a regular incandescent lamp to with an adapter, if it lights the ballast is working ( I did not say good)
We have replaced all our HIDs with L.E.D (manufacturer) screw in LED lamps. Have done most of the HPS as well. Will last until the next generation of electrician in 30 years.

 

[kwired]

You can use a regular incandescent lamp to with an adapter, if it lights the ballast is working ( I did not say good)
We have replaced all our HIDs with L.E.D (manufacturer) screw in LED lamps. Have done most of the HPS as well. Will last until the next generation of electrician in 30 years.

Guaranteed to work that long?

Don't know your age but do you promise to personally fix it when you are 80-90 years old if it fails then?

 

[iwire]

Five years of constant use and we are seeing many failures.

 

[cleatus_sask]

I use a Greenlee ballast tester- has a loop for a clamp-on meter... 100% accurate. .. I relamp our fixtures when the 400wmh bulbs go out, change 1 ballast for every 50 bulbs!