PROBLEM 1

LAMP WILL NOT START

PROBLEM 2

LAMP LIFE IS REDUCED

PROBLEM 3

LAMP FLICKERS OR CYCLES ON AND OFF

PROBLEM 4

LAMP STARTS SLOWLY (ARC DOES NOT STRIKE WHEN 
SWITCH IS TURNED ON.)

PROBLEM 5

FUSES BLOW OR CIRCUIT BREAKERS OPEN ON LAMP START UP

PROBLEM 6

LAMP LIGHT OUTPUT LOW

PROBLEM 7

ARC TUBE BECOMES BLACKENED OR SWOLLEN EARLY IN LIFE OR LAMP/ARC TUBE MAY SHOW SIGNS OF SCORCHING

PROBLEM 8

DIFFERENCE IN LAMP COLORS POSSIBLE CAUSE CORRECTIVE ACTION

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Lamp Physically Damaged

Investigate the possibility of outer bulb damage from handling or transportation that may have cracked glass. If air enters outer bulb, arc tube may continue to burn for 100 hours before failure. Check to see if the bulb is broken where glass meets the base due to twisting lamp too firmly into socket or scoring of glass where socket inadvertently touches the lamp bulb. Look for broken arc tube or loose metal parts. A leak in the outer bulb will cause oxidation of the metal parts inside. In high pressure sodium, the dark gettering material in the neck of the bulb near the base will turn white or disappear. Replace lamp.

2. Wrong Ballast

Make sure that the ballast label agrees with the line voltage and the installed lamp. The 1,000 watt Mercury lamp, for example, is made in the H34 (High Current) and the H36 (Low Current) types with a separate ballast available for each type. If the H34 ballast is used with the H36 lamp or vice versa, the life of the lamp will be adversely affected and can destroy the ballast. A similar situation exists with S55, S56 and S63 150 watt high pressure sodium lamps. 

3. Lamp Operating in Incorrect Position

Either change positioning of fixture or replace lamp with one suitable for that position.

4. Faulty Capacitor

To check capacitor, disconnect and discharge it. Then, using an ohmmeter, set to the highest scale, check for faults, 1) if meter reads low resistance initially and increases, capacitor is good. 2) if meter reads low resistance initially and remains the same, the capacitor is SHORTED and should be replaced. 3) if meter reads high resistance initially and remains the same, the capacitor is OPEN and should be replaced.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Wrong Ballast

With mercury lamps, improper ballasting can cause flickering or erratic operation. With metal halide lamps, the effect is generally noticed in the startup period when the lamp ignites, starts to warm up and then extinguishes (cycling). This may be caused by improper voltage/current relationships delivered by ballast. Under certain conditions new lamps may "cycle". Usually after three tries to start at 30 to 60 second intervals lamps will stabilize and operate normally.

2. High Lamp Operating Voltage/Low Open Circuit Ballast Voltage

Measure lamp operating voltage. Measure ballast open circuit voltage. Replace as required.

3. Variable Voltage

Heavy motor loads or welding appliances on line can cause flickering during operation. Remove lighting circuits from the circuits serving these devices. Provide voltage regulators. Check for loose connection. Use of Constant Wattage Isolated (CWI) ballasts not Constant Wattage Auto (CWA) can frequently help this situation.

4. HPS Cycler

As a high pressure sodium lamp is burned for long periods of time, its operating voltage tends to increase. When this point is reached, the lamp will exhibit cycling on and off characteristics. This is normal end of life lamp. Replace the lamp after checking ballast open circuit voltage and lamp operating voltage.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Hard Starter

A hard starter is a lamp which will not start rapidly. It may glow for extended periods of time destroying cathodes. It should be replaced after checking voltage and ballast.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Overloaded Circuit

Rewire to accommodate starting current of lamp/ballast combination.

2. High Momentary Transient Current

Can be caused by reactor or autotransformer ballasts which draw high initial currents. Use current protective devices incorporating time delay elements. If these fail, change ballast as its characteristics will affect lamp life.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Normal Light Output Depreciation Throughout Life

Refer to maintenance characteristics of lamp in technical publications comparing light output vs. burning time. If depreciation is within published range, replace lamp.

2. Incorrect Voltage

Check ballast label to see if rating designation conforms to lamp rating description. Correct if necessary. Check line voltage at ballast and set ballast tap to voltage reading. If not tapped, check ballast voltage range against input voltage. Check wiring connections for voltage loss points. Check socket contact point. Use CWI ballast.

3. Incorrect Ballast Output

Check ballast output to determine if it conforms to lamp requirements. If voltage and current do not stabilize in five to ten minutes warm-up time, ballast output is incorrect and adjustment should be made. Check capacitor wiring, if visibly available, to determine if capacitors are properly wired.

4. Dirt Accumulation

Check and clean lamp and luminaire. Establish maintenance program.

5. Faulty Capacitor

Check capacitor rating to specification. Measure capacitance to specification using capacitance meter. Replace capacitor if necessary.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Over wattage Operation Improper Ballasting

Check for possibility that lamp is operated on ballast designed for higher wattage lamp. Over wattage operation can cause premature blackening. Check ballast label against lamp specification.

2. Excessive Current or Shorted Capacitor(s)

Check voltage at ballast. Check for possibility of current or voltage surges which can damage arc Voltage tube or seals or burn up connecting ribbons inside outer tube. Check for shorted capacitors and replace ballast if shorts are found.

3. Reflector Problem

Reflector design may refocus radiant energy directly on the arc tube or other parts of the lamp causing overheating. Limits for allowable voltage rise due to fixture effect are listed in High Pressure Sodium Engineering Bulletins. If this is suspected, the luminaire should be tested in a laboratory.

4. "Glow State" Operation

Under certain lamp and/or ballast operating conditions, lamps will go into a partial discharge (dim glow) which will darken arc tube and cause short life. Replace lamp and check ballast.

POSSIBLE CAUSE

CORRECTIVE ACTION

1. Normal Maintenance

In addition to the normal decrease in light output or brightness, a color shift can occur as lamps age. Spot replacement of failures with new lamps may show very noticeable differences in lamp colors. A group re-lamping program minimizes this problem.

2. Wrong Lamp Color

Check etch on lamps which appear different to see that they are actually the same color. Replace with correct color lamp.

3. Range of Manufacturing Tolerances

Due to tolerance ranges from manufacturers, slight differences in color can be corrected by grouping those of similar color.

4. Variations in Luminaires

Variations in the surface or finish of the reflectors and/or lenses can introduce color differences. Interchange lamps to check on possible luminaire differences. Dirty fixtures can also create differences, emphasizing the importance of adequate maintenance.

5. Variations in the Environment

In common with luminaire variations, color differences in ceilings, walls, floors and furnishings as well as other sources of illumination in the area can affect the appearance of the lamp color.

6. Faulty Capacitor

Check capacitor rating to specification. Measure capacitance to specification, using capacitance meter. Replace capacitor if necessary.