KW or KVA
#1
Member
Thread Starter
Join Date: Aug 2015
Location: Philippines
Posts: 77
Upvotes: 0
Received 0 Upvotes
on
0 Posts
KW or KVA
So, I have an ACCU with 9.2 KVA. The electrical characteristics of the ACCU is 4.30 KW, single phase, 230 Volts. The question is what current should I use for sizing the breaker - the one from KVA or the one from KW.
I = 9.2 KVA/230 = 40 A
I = 4.3 KW/230 = 18.7 A
I = 9.2 KVA/230 = 40 A
I = 4.3 KW/230 = 18.7 A
#5
Member
engrkira, while you are explaining, another dumb question. Since VA = W, why the difference?
Bud
Bud
#6
Member
Thread Starter
Join Date: Aug 2015
Location: Philippines
Posts: 77
Upvotes: 0
Received 0 Upvotes
on
0 Posts
I have 2 ratings here and I don't know what to use. Maybe you should read again. I know that in a single phase VA = W but then there are 2 ratings presented so I am asking questions. Read First before posting.
#7
Member
"Read First before posting." That isn't a very friendly reply, try again.
I did read and you didn't answer the question, yet you already bought a breaker. The breaker size should protect the wire and the wire and breaker should be large enough to not trip during normal operation.
What size wire did you install?
Bud
I did read and you didn't answer the question, yet you already bought a breaker. The breaker size should protect the wire and the wire and breaker should be large enough to not trip during normal operation.
What size wire did you install?
Bud
#9
Member
VA only equals watts with resistive loads. The full formula is KVA times Power Factor = KW. When you have inductive (or capacitive) loads like motors and fluorescent lighting, the current and voltage are not in phase. This phase difference is represented by the power factor. Resistive loads have a power factor of 1, but motors and the like will have a smaller power factor.
When you size the wiring for big inductive loads, such as the ACCU, you use the KVA rating because that tells you what the current flowing to the load will be, and it's the current that determines the wire size and breaker size needed.
When you size the wiring for big inductive loads, such as the ACCU, you use the KVA rating because that tells you what the current flowing to the load will be, and it's the current that determines the wire size and breaker size needed.
#10
Member
Thanks CT. My electronics background never had to deal with motors and phase relationships, although I do understand them. Makes sense.
Bud
Bud