Indicating lamps in motor controls
- Thread starter musthafa
- Start date
- Status
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
In general, the reasons for using of low voltage lamps in pilot lights is twofold:
Most people will now accept LED lamps in lieu of having a transformer because in addition to the above, the LEDs last longer. I have yet to meet an engineer who would reject an LED substitute when transformer type pilot lights are specified.
- The lower voltage means the lamp filament itself is thicker and makes it less susceptible to vibration
- Some people feel it is safer the have lower voltage bulbs because when changing them, they are not exposed to hazardous voltages (defined as over 50VAC)
Most people will now accept LED lamps in lieu of having a transformer because in addition to the above, the LEDs last longer. I have yet to meet an engineer who would reject an LED substitute when transformer type pilot lights are specified.
broadgage
Senior Member
- Location
- London, England
As above, and also 230 volt incandescent pilot lamps are not readily available, and 400 volt virtually unobtainable.
Neon pilot lamps are available in these voltages but are very dim, and in any colour other than red/orange, dont seem to last long.
LED pilot lamps are becoming more common, but some types can be wastfull on 400 volt supplies.
LEDs operate at only a few volts, and generally use a resistor in series at higher voltages. On a 400 volt supply the waste in the resistor can be several watts.
A low voltage incandescent lamp might use in total 2 watts (1 watt lamp, 50% transformer efficiency)
The incandescent lamp will also be brighter than most LEDs.
Neon pilot lamps are available in these voltages but are very dim, and in any colour other than red/orange, dont seem to last long.
LED pilot lamps are becoming more common, but some types can be wastfull on 400 volt supplies.
LEDs operate at only a few volts, and generally use a resistor in series at higher voltages. On a 400 volt supply the waste in the resistor can be several watts.
A low voltage incandescent lamp might use in total 2 watts (1 watt lamp, 50% transformer efficiency)
The incandescent lamp will also be brighter than most LEDs.
Thank you Jraef and broadgage.
Even though the safety aspect and power consumption are good reasons, I hope the specifier may more concern about the vibration inside the MCC panel. Because in the same specification he does not insist to provide these type of lamps in the Main Switch gear panel.
Even though the safety aspect and power consumption are good reasons, I hope the specifier may more concern about the vibration inside the MCC panel. Because in the same specification he does not insist to provide these type of lamps in the Main Switch gear panel.
mdshunk
Senior Member
- Location
- Right here.
I'd rather think that's the sort of oversight that happens when a fellow cuts and pastes specs, rather than wanting two different types for a special reason.
- Status