Input Wattage for mix and match ballast & lamps

Status
Not open for further replies.
I am trying to estimate actual wattage in a high bay fixture with 400W HPS ballast, utilizing 250W HPS lamps. Is there a formula for this or way to estimate?

Any help is appreciated.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
190622-1426 EDT

thewiseguy31:

We need to know what you are talking about.

Gaseous discharge devices are what can be described as constant voltage devices. A constant voltage device is something that has a moderately constant voltage drop somewhat independent of the current flowing thru it.

A spark, an arc, a fluorescent bulb, an LED, a diode, an HPS, a pentode vacuum tube, a battery, a DC generator, and other similar things fall in this category.

You can not directly parallel such devices unless their voltages match.

A ballast is a device designed to provide a somewhat constant current source and as a single device would be coupled with a single constant voltage load.

Gaseous discharged devices also have some initiating voltage that is higher than their running voltage. A typical neon bulb, NE-2, might require 100 V to breakdown, but then drops to about 60 V when glowing. For 120 V pilot lights a neon bulb may have a 100 k series resistor for current limiting. Look at the bulb voltage drop on a scope, and you will see the breakdown voltage and the glow voltage.

.
 
Status
Not open for further replies.
Top