Need help with a Resistor

[ericanderson]

I need to find a 1.5k ohm 20watt or greater resistor.
I am having trouble finding one of this wattage and was wondering if I can combine two 10watt resistors in parellel would that be the same?
Thanks for any help ...
Eric

 

[Nigel Goodwin]

I need to find a 1.5k ohm 20watt or greater resistor.
I am having trouble finding one of this wattage and was wondering if I can combine two 10watt resistors in parellel would that be the same?
Thanks for any help ...
Eric

Yes you could, or in series for that matter, but you should place them fairly well apart so air can circulate.

What do you need the resistor for?, it would require 173V to dissipate 20W in a 1.5K resistor.

 

[Dean Huster]

Two 10-watt 3.0K in parallel or two 10-watt 750 ohm resistors in series will do the trick. Whether it's series or parallel doesn't matter as far as two resistors sharing the load as long as you alter the values so that the equivalent value is your desired value. Equal value resistors in either arrangement guarantees that each resistor will share the load. Using a really small resistor in parallel with a larger resistor to get your desired value could have disastrous effects on the smaller resistor as it may overdissipate. It's similar with a series circuit except that the larger of the two resistor will suffer.

Dean

 

[ericanderson]

Dean,
Thank you so much for your help.
A Tech person at Lutron told me I could use a 1.5k ohm 20w resistor across the primary side of the coil of a relay to fake out their "Grafik Eye" dimmer into thinking the relay primary coil was a load similar to a light.
The relay would then switch a florescent light with an electronic ballast.
He said that florescent lights have a great spike of current draw when they are first turned on and over time that would ruin the dimmer switch.
Thanks again...
Eric

 

[Nigel Goodwin]

Dean,
Thank you so much for your help.
A Tech person at Lutron told me I could use a 1.5k ohm 20w resistor across the primary side of the coil of a relay to fake out their "Grafik Eye" dimmer into thinking the relay primary coil was a load similar to a light.
The relay would then switch a florescent light with an electronic ballast.
He said that florescent lights have a great spike of current draw when they are first turned on and over time that would ruin the dimmer switch.

I don't really see why you would want to switch a florescent light on via a dimmer and a relay?. I'm presuming you want the light to be ON above a certain power setting, and OFF below a certain power setting (probably using full power, and zero power).

Is this just to implement a light switch, on a lighting system which doesn't really support switching florescent lights?.

Certainly florescents do have a high switch-on surge, and it could well damage a dimmer if fed via it (but it's not normally something you would do).

 

[gerty]

allelectronics.com has 1.6k 30watt resistors for $1.00 each....
Is that close enough for you

 

[ericanderson]

This will work ! Thanks so much !
I just ordered one. (more for shipping than the resistor, but hey, I dont have to drive out to get it)
Thanks again ...
Eric