Wilburt Light Tower Bulbs Blowing Out

[MG3610]

We have a 2010 Pierce HDR with two Wilburt Light Masts. The truck is running a 50Kw direct drive generator. Over the last few months since its delivery, we have had numerous bulbs in each tower blow out. We have Magnafire 1500W lightheads. The dealer suggested and says they have changed our bulbs from 240W to 277W, as they felt a slight voltage fluctuation was the culprit for blowing the bulbs. If the bulbs were in fact changed, they are still blowing out.

I also noticed last night one of the 900w HIR bulbs in our Optimum body mounted lights is out. This truck is only 7 months old.

Is anyone else exopierencing this?

[islandfire03]

Sounds like more than a slight voltage fluctuation, What does the dealer say about getting a qualified electrician to run a load test on the output from the generator?.

50 kw takes a lot of horsepower to produce and with throttle changes there may be variation surges wide enough to blow the bulbs.
Are they covering this as a warrantee item?
They should be!

[plumb25]

One thing you can check is the hertz on the generator, too low or too high can cause the bulbs to blow. Also, are you letting the generator to spool up to the proper hertz before turning the light on? If not the ramp up can also blow bulbs.

[MG3610]

One thing you can check is the hertz on the generator, too low or too high can cause the bulbs to blow. Also, are you letting the generator to spool up to the proper hertz before turning the light on? If not the ramp up can also blow bulbs.

In order for the light towers to operate, you have to raise them, after engaging the generator. I'd say thats a good minute or two of time from engagement to lightheads illuminated.

[MG3610]

Sounds like more than a slight voltage fluctuation, What does the dealer say about getting a qualified electrician to run a load test on the output from the generator?.

50 kw takes a lot of horsepower to produce and with throttle changes there may be variation surges wide enough to blow the bulbs.
Are they covering this as a warrantee item?
They should be!

Thank you for this suggestion. As far as I know we havent paid a cent yet for any bulbs.

[chiefengineer11]

Sounds like more than a slight voltage fluctuation, What does the dealer say about getting a qualified electrician to run a load test on the output from the generator?.

50 kw takes a lot of horsepower to produce and with throttle changes there may be variation surges wide enough to blow the bulbs.
Are they covering this as a warrantee item?
They should be!

Second the motion of having an electrician check it. Our 10+ year old Will-Burt tower has six FRC Focus 240V 1500W light heads on it, and that's never been a problem for us.

Also, today's control systems are for the most part, so good that voltage variation problems shouldn't be an issue unless there's a fault with your controller. Do you hear any engine speed changes going on when it's in operation? I was just looking at the truck on your web site and I don't see anything on it, such as a main pump, that would normally cause variations.

How about vibration? Although I wouldn't expect any, it's something to look at. Do the masts look steady when they're extended and in operation? If you got up there and put your hand on a one, could you feel anything? By the way, what is the engine RPM when the gen set is in operation? There might possibly be a harmonic vibration that could be hard to detect.

Just a few of my thoughts.

[MG3610]

Second the motion of having an electrician check it. Our 10+ year old Will-Burt tower has six FRC Focus 240V 1500W light heads on it, and that's never been a problem for us.

Also, today's control systems are for the most part, so good that voltage variation problems shouldn't be an issue unless there's a fault with your controller. Do you hear any engine speed changes going on when it's in operation? I was just looking at the truck on your web site and I don't see anything on it, such as a main pump, that would normally cause variations.

How about vibration? Although I wouldn't expect any, it's something to look at. Do the masts look steady when they're extended and in operation? If you got up there and put your hand on a one, could you feel anything? By the way, what is the engine RPM when the gen set is in operation? There might possibly be a harmonic vibration that could be hard to detect.

Just a few of my thoughts.

No pump. Only a PTO driven Vanair Compressor. No audibly detectable RPM fluctuations, I'll have to watch the tachometer next time I run it.

[KB1OEV]

One thing you can check is the hertz on the generator, too low or too high can cause the bulbs to blow. Also, are you letting the generator to spool up to the proper hertz before turning the light on? If not the ramp up can also blow bulbs.

The "hertz" is a unit of frequency. What you are saying is to check the frequency, which will be some number of hertz; equivalent to cycles per second.

A variation in frequency will not cause any problems with direct drive AC incandescent lights. Electronics or lights with an AC to DC converter (LEDs) or ballast (fluorescent or HID) could have problems with an incorrect frequency power source.

It sounds to me like you are either getting voltage spikes or the bulbs are being stressed by impacts or road vibration. You may want to check the voltage regulator on the generator or see if bulbs rated for a slightly higher voltage are available.

[FIREMECH1]

I've got 2 rescues with the Will-Burt towers, with 4 1500w, 240v systems on an Onan 40kw gen. If your blowing bulbs that fast and hard, you need to have someone (certified) to take a look at the regulator on it. From the sounds of it, it is spiking the bulbs, and blowing them.

It might be of interest to check behind the reflectors as well. I've found that on a couple aerials that use the same bulbs, had wires rubbed through the insulation on the wiring. One day it would work fine, then it wouldn't the next. Bulb was blown on each occurrence. I found it by lighting it up, and using a broom handle to "bang" it around. Finally it blew the bulb, and found the wiring issue.

FM1