# Please could someone explain what the cos means

Discussion in 'Homework Help' started by ElecNerd, Jan 2, 2011.

1. ### ElecNerd Thread Starter New Member

Jan 2, 2011
20
0
Hi,

Whilst I understand the following in terms of identifying the phase and line voltages etc please could someone advise me what I would put into the calculator for cosθ as detailed below. I seem to understand it and then they throw this in for good measure .

In case of delta conneted load in above fig(a) the total active power is equal to three times the power of one phase.

Since the line current in the balanced delta connected loads is

substituting this eq the total active power becomes

Thank you very much for your help!

2. ### edgetrigger Member

Dec 19, 2010
133
20
cosθ is the phase agle between the current and the voltage. If you are calculating for a resistor just enter 0 in the calculator, or cos0 = 1 , you could ignore it for a resistor

3. ### edgetrigger Member

Dec 19, 2010
133
20
furhter for a pure inductor or a capcitor θ = 90. Mind you, you have to set the calculator to degree mode before doing calculations. If it is in radian then calculation will go for a toss.

Last edited: Jan 2, 2011
4. ### hgmjr Retired Moderator

Jan 28, 2005
9,030
218
The cosine of the phase between the voltage and the current is also referred by the term "power factor".

hgmjr

5. ### ElecNerd Thread Starter New Member

Jan 2, 2011
20
0
Thanks everyone for taking the time to answer this for me - much appreciated