Defrost Elements in series?

[Drew]

Hi Guys,
In Tasmania we have 240v supply. Originally on a evaporator I had 2 x 1,6kw 115v defrost elements in series connected to the 240v.
These elements blew so the suppliers sent me 2 x 3,2kw 240v defrost elements.
If I connect these in series to 240v will they give me the same amount of heat (Kw) as the originals?

[Drew]

I should have mentioned that the original elements blew after 8 years and they where wired up correctley

[philfridge]

No do not connect these elements in series ! . You can fit these element but wire them up in parellel . One element will give you 3.2 kw the same as the two 1.6 kw elements you had before in series.

[SteinarN]

Hi Guys,
In Tasmania we have 240v supply. Originally on a evaporator I had 2 x 1,6kw 115v defrost elements in series connected to the 240v.
These elements blew so the suppliers sent me 2 x 3,2kw 240v defrost elements.
If I connect these in series to 240v will they give me the same amount of heat (Kw) as the originals?

Two 3.2 kW elements in series will give you a total of 1.6 kW. Thus you get only half the capasity you had previously. If you need two elements, the alternatives these elements is giving you is: series 1.6 kW total, and paralell 6.4 kW total.

[DIVEJUDE]

Maths:

Power=Voltage*Current
Voltage=Current*Resistance
Power=Voltage*Voltage/Resistance


2*3.2kw heaters 240v

Resistance=Voltage*Voltage/Power
therefore
Resistance=240*240/3200
say approx 20 ohms

Resistance in series will mean total resistance of approx 40 ohms with a voltage of 240v
therefore power will halve to 1.6kW

Resistance in parallel would have 2 lots of 3.2kW totalling 6.4kW.

Very confusing but hope this helps.

[chillin out]

Wait a minute, if he had 2 * 1.6kw 115v in series and got 2 * 3.2kw 240v.
How would these ever fit?

2 * 3.2kw in series gives 1.6kw
Therefore 2 * 1.6kw in series would give 0.8kw

Or am I missing something because of the voltage?

Chillin

[nike123]

You should fit only one element for same power as before.

[SteinarN]

Wait a minute, if he had 2 * 1.6kw 115v in series and got 2 * 3.2kw 240v.
How would these ever fit?

2 * 3.2kw in series gives 1.6kw
Therefore 2 * 1.6kw in series would give 0.8kw

Or am I missing something because of the voltage?

Chillin

Yep, you are missing the voltage. The new elements is 240 V, therefore 2*3.2 kW in serie gives only 25% of total power, IE 25% of 6.4 kW total is 1.6 kW total.
The old elements was 115 V, therefore 2*1.6 kw in serie at 240V gives 100% of total power IE 100% of 3.2 kW is 3.2 kW.

But you are right, these elements wount give the same capasity as the old elements if it is necessary to install both elements for proper distribution of the heat.

[Peter_1]

This must do and the rest is up to you http://www.the12volt.com/ohm/ohmslaw.asp