Lighting Circuit Current 2

[sgtan1]

Hi,

Just wondering if anyone could help me with calculating the current that should be running in a typical HPSV Lighting circuit. (teach me how to read the data sheet)

Considering a 400W lamp - Magnetic Ballast - Ignitor - P.F.Capacitor

Should I sum all the power loss + 400W.
Do I need to consider the current drawn by the P.F Capacitor?

Anywhere on the

http://WWW I

can read up on this?

Thanks

 

[waross]

Look for "Line Current" on the data sheet.
Summing Watts out and losses will give you the total watts but will not infer the current.
You may also have reactive currents. With cheaper ballasts you may expect greater reactive currents. The capacitor may not be correcting the power factor to unity.
respectfully

 

[sgtan1]

Thanks waross,

I guess it is implied that the ballast line current would be covering the lamps and P.F correction capacitor?

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Looking at a data sheet from phillips BSN40L407ITS. The current listed would it be inclusive with the P.F correction as no indication on this... I assume that with this we can basically ignore the data on the lamps that is attached assuming appropriate types?

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Unfortunately there do not seem to be any current listed on the datasheet I have. Only
Lamp
Wattage (W) 400
Operating voltage (V) 100
Operating lamp current (A) 4.4
Max. starting current (A) 8.5

Ballast
Nominal wattage 400
Losses (W) 36
Impedance (W) 46
Resistance (W) 0.95 ± 0.10
Inductance (H) 0.15
Power factor before correction 0.42
Power factor after correction 0.99

Capacitor used 45uF

I just realized that they put Resistance & impedence in W so back to excel...

Would be grateful on advice to use this. At work everyone uses "rule of thumb" 1.8 x Lamp Power to get the Apparent Power for design assumptions. I'm trying to verify this.

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Merry Holidays and a Happy New Year!

 

[Skogsgurra]

Hey! They did not put resistance and impedance in watts.

It is not possible to do so. What happened is that the greek letter "omega" got translated to "W". It happens now and then. The reason is that little omega looks like "w" - only more rounded shape - and somewhere inside Gates' brainchild has got confused with any character looking like it. Which happened to be "W".

Also, I cannot understand why you say "Unfortunately there do not seem to be any current listed on the datasheet I have". There is both operating current and maximum starting current. Go easy with your Excel sheets. Get an understanding before applying automation.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[waross]

I would use the maximum starting current of 8.5 amps for circuit design. This will be the current that your breakers must pass when the circuit is switched on. The wire size should also be determined by this value so that the conductors are properly protected by the breaker.
Operating lamp current (A) 4.4A X 1.8 = 7.92A The 8.5A is not far off the rule of thumb figure.
I suggest using the current that is given (8.5A) and accepting that the rule off thumb verifies it as reasonable.
Thanks for the explanation, Gunnar. I was wondering about those units.
Respectfully

 

[dpc]

http://www.advancetransformer.com/uploads/resources/RT-8060-R02_web.pdf

I'm not quite sure what you are really looking for. If you are just interested in the current requirements for a particular HPS light fixture, just use the normal current input for the corresponding ballast. You can forget about the lamp - it gets all of its current from the ballast.

Any ballast supplier should be able to give you this information. It will take into account power factor, ballast losses, etc.

 

[sgtan1]

Thanks, Gunnar for pointing that Omega thing out.

thanks, dpc, I was suspecting that it should be base on the ballast's as well but not sure if the value already considered the correction or not and as Waross point out we should really be looking at the staring current.