Simple Help

[Paul Stafford]

Please answer in words of one syllable as my electrical skills are not all
that!

The problem: I have a compressor rated at 340 watts 2.4 amps, with a
startup of 4.5 amps max and runs at 240 volts.

I am after a genrator to run this outside and purchased one last year with
an output of 700 watts, but the compressor did not work. I have since been
advised that I need a generator with an output of 2.3KVA.

As I said, I need a simple answer, but do the numbers add up here? I have
had two people tell me that the first generator should have worked. Does
the 2.3 KVA seem high? The person that told me that, sold me the
compressor, but was not selling a generator, so had nothing to gain, but I
am puzzled.

Any thoughts, please?

Thanks

paul

 

[Dan Hollands]

700W clearly won't do it

VA is volt times amps

To Start the compressor you need 240 x 4.5 = 1080 VA or 1.08 KVA

I agree that a 2.3KVA generator would be a good choice

note that Watts and VA are similiar. Watts implies a resistive load and VA
may be an inductive load which is what the compressor motor is.
--

Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
QuickScore@USSailing.net
www.QuickScoreRace.com


"Paul Stafford" <paul_stafford@blueyonder.co.uk> wrote in message
news:KUbwe.35110$Vo6.15448@fe3.news.blueyonder.co.uk...

Please answer in words of one syllable as my electrical skills are not all
that!

The problem: I have a compressor rated at 340 watts 2.4 amps, with a
startup of 4.5 amps max and runs at 240 volts.

I am after a genrator to run this outside and purchased one last year with
an output of 700 watts, but the compressor did not work. I have since
been advised that I need a generator with an output of 2.3KVA.

As I said, I need a simple answer, but do the numbers add up here? I have
had two people tell me that the first generator should have worked. Does
the 2.3 KVA seem high? The person that told me that, sold me the
compressor, but was not selling a generator, so had nothing to gain, but I
am puzzled.

Any thoughts, please?

Thanks

paul

 

[Pat Ziegler]

Paul:

A couple of things to help you understand the problem here.

First, a little watts law. W=I(amps) X V(volts)

So, 240V X 2.4A = 576W

At start, 240V AX 4.5A = 1080W

To convert Watts to VA (volt amps) We need to know the "Power Factor"
of the generator. I would guess it is something like .8 So, you would
take 1080W X .8 = 864 VA


Now, A compressor is not the best load to connect to your generator.
It is a very "Inductive" load plus things like current and phase are always
changing. (An inexpensive generator would have much trouble with this load)

It would not be unreasonable to oversize the generator by 2X because of
the type of load the compressor presents to the generator.

So, 1.7KVA or 2100Watts


My recommendation is instead of buying a bigger generator that you buy a gas
powered compressor. Then you have less stuff working and it will be way
more efficient.


Visit us at

www.weisd.com for your electronic needs

Thanks

Pat Ziegler
Wholesale Electronics Inc.








"Paul Stafford" <paul_stafford@blueyonder.co.uk> wrote in message
news:KUbwe.35110$Vo6.15448@fe3.news.blueyonder.co.uk...

Please answer in words of one syllable as my electrical skills are not all
that!

The problem: I have a compressor rated at 340 watts 2.4 amps, with a
startup of 4.5 amps max and runs at 240 volts.

I am after a genrator to run this outside and purchased one last year with
an output of 700 watts, but the compressor did not work. I have since
been
advised that I need a generator with an output of 2.3KVA.

As I said, I need a simple answer, but do the numbers add up here? I have
had two people tell me that the first generator should have worked. Does
the 2.3 KVA seem high? The person that told me that, sold me the
compressor, but was not selling a generator, so had nothing to gain, but I
am puzzled.

Any thoughts, please?

Thanks

paul

 

[Paul Stafford]

Brilliant - thanks for your help. All is clear now.

Paul


"Dan Hollands" <dhollan3@rochester.rr.com> wrote in message
news:9odwe.42459$fp6.3779@twister.nyroc.rr.com...

700W clearly won't do it

VA is volt times amps

To Start the compressor you need 240 x 4.5 = 1080 VA or 1.08 KVA

I agree that a 2.3KVA generator would be a good choice

note that Watts and VA are similiar. Watts implies a resistive load and VA
may be an inductive load which is what the compressor motor is.
--

Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
QuickScore@USSailing.net
www.QuickScoreRace.com


"Paul Stafford" <paul_stafford@blueyonder.co.uk> wrote in message
news:KUbwe.35110$Vo6.15448@fe3.news.blueyonder.co.uk...
Please answer in words of one syllable as my electrical skills are not
all that!

The problem: I have a compressor rated at 340 watts 2.4 amps, with a
startup of 4.5 amps max and runs at 240 volts.

I am after a genrator to run this outside and purchased one last year
with an output of 700 watts, but the compressor did not work. I have
since been advised that I need a generator with an output of 2.3KVA.

As I said, I need a simple answer, but do the numbers add up here? I
have had two people tell me that the first generator should have worked.
Does the 2.3 KVA seem high? The person that told me that, sold me the
compressor, but was not selling a generator, so had nothing to gain, but
I am puzzled.

Any thoughts, please?

Thanks

paul

 

[John Fields]

On Tue, 28 Jun 2005 10:11:21 -0500, "Pat Ziegler" <pzig@weisd.com>
wrote:

Paul:

A couple of things to help you understand the problem here.

First, a little watts law. W=I(amps) X V(volts)

So, 240V X 2.4A = 576W

At start, 240V AX 4.5A = 1080W

To convert Watts to VA (volt amps) We need to know the "Power Factor"
of the generator.

---
No, you need to know the power factor of the load.
---

I would guess it is something like .8 So, you would
take 1080W X .8 = 864 VA

---
Hmmm... a perpetual motion machine!!!

Frayed knot...

Assuming that that inrush _was_ 1080 watts, and the load had a power
factor of 0.8


P = VA cos(phi)

then
P 1080W
VA = ---------- = ------- = 1350VA
cos(phi) 0.8

Now, A compressor is not the best load to connect to your generator.
It is a very "Inductive" load plus things like current and phase are always
changing. (An inexpensive generator would have much trouble with this load)

It would not be unreasonable to oversize the generator by 2X because of
the type of load the compressor presents to the generator.

So, 1.7KVA or 2100Watts

---
Wrong again. 1350VA *2 = 2700VA = 2.7kVA.
---

My recommendation is instead of buying a bigger generator that you buy a gas
powered compressor. Then you have less stuff working and it will be way
more efficient.


Visit us at

www.weisd.com for your electronic needs

---
If your solutions for fulfilling electronic needs are as good as your
advice so far, perhaps a Burger King franchise might be more in line
with your capabilities.


--
John Fields
Professional Circuit Designer

 

[Pat Ziegler]

Thanks for making my point!

Very mature




"John Fields" <jfields@austininstruments.com> wrote in message
news:6l33c1lrc4hoksvih9keooojo8q82e6km6@4ax.com...

On Tue, 28 Jun 2005 10:11:21 -0500, "Pat Ziegler" <pzig@weisd.com
wrote:

Paul:

A couple of things to help you understand the problem here.

First, a little watts law. W=I(amps) X V(volts)

So, 240V X 2.4A = 576W

At start, 240V AX 4.5A = 1080W

To convert Watts to VA (volt amps) We need to know the "Power
Factor"
of the generator.

---
No, you need to know the power factor of the load.
---

I would guess it is something like .8 So, you would
take 1080W X .8 = 864 VA

---
Hmmm... a perpetual motion machine!!!

Frayed knot...

Assuming that that inrush _was_ 1080 watts, and the load had a power
factor of 0.8


P = VA cos(phi)

then
P 1080W
VA = ---------- = ------- = 1350VA
cos(phi) 0.8


Now, A compressor is not the best load to connect to your generator.
It is a very "Inductive" load plus things like current and phase are
always
changing. (An inexpensive generator would have much trouble with this
load)

It would not be unreasonable to oversize the generator by 2X because
of
the type of load the compressor presents to the generator.

So, 1.7KVA or 2100Watts

---
Wrong again. 1350VA *2 = 2700VA = 2.7kVA.
---

My recommendation is instead of buying a bigger generator that you buy a
gas
powered compressor. Then you have less stuff working and it will be way
more efficient.


Visit us at

www.weisd.com for your electronic needs

---
If your solutions for fulfilling electronic needs are as good as your
advice so far, perhaps a Burger King franchise might be more in line
with your capabilities.


--
John Fields
Professional Circuit Designer

 

[John Fields]

On Tue, 28 Jun 2005 14:22:08 -0500, "Pat Ziegler" <pzig@weisd.com>
wrote:

Thanks for making my point!

---
Your point being that you don't acknowledge correction but, rather,
prefer to skirt the issue and deal in personalities?
---

Very mature

---
Is it mature to dodge the issue?

--
John Fields
Professional Circuit Designer

 

[Pat Ziegler]

John:


I am not dodging anything.

My point is that you fly way too far off the handle. You use rude &
foul language in a public forum yet you seem to hate me because I had the
gaul to advertise my business in this forum. So, I can't invite someone to
visit my website but yet you are free to rant and rave all you want.

I have no problem with your correction, In the end I think my
suggestion to purchase a gas powered compressor is the still the correct
answer. Why buy a generator to power an electric compressor when they make
gas powered compressors? Seems simple enough to me.


I understand you do not like spam, Who does? and I apologize for
sending you my post yesterday, It was not intended for you. But at least I
did it politely.

My advice to you is to settle down, All this high tension is bad for
the old ticker.....


Pat Ziegler







"John Fields" <jfields@austininstruments.com> wrote in message
news:mr93c1h5r6e6n657bv51t9kfa8ngl2j07u@4ax.com...

On Tue, 28 Jun 2005 14:22:08 -0500, "Pat Ziegler" <pzig@weisd.com
wrote:

Thanks for making my point!

---
Your point being that you don't acknowledge correction but, rather,
prefer to skirt the issue and deal in personalities?
---

Very mature

---
Is it mature to dodge the issue?

--
John Fields
Professional Circuit Designer

 

[John Fields]

On Tue, 28 Jun 2005 15:46:17 -0500, "Pat Ziegler" <pzig@weisd.com>
wrote:

John:


I am not dodging anything.

My point is that you fly way too far off the handle. You use rude &
foul language in a public forum yet you seem to hate me because I had the
gaul to advertise my business in this forum. So, I can't invite someone to
visit my website but yet you are free to rant and rave all you want.

---
I certainly don't hate you, and I haven't criticized you advertising
your business in this or any other public forum, I criticized your
sending me SPAM via private email and then defending the action rather
than offering an apology. I am abrasive on occasion and I use foul
language whenever, in my opinion, it's warranted. YMMV. You're free
to do whatever you want to here, but you need to be aware that if what
you do pisses people off you're going to hear about it. Welcome to
Usenet.
---

I have no problem with your correction, In the end I think my
suggestion to purchase a gas powered compressor is the still the correct
answer. Why buy a generator to power an electric compressor when they make
gas powered compressors? Seems simple enough to me.

---
Because he already has a compressor and if he gets a generator he can
use the generator for other things if he wants to?
---

I understand you do not like spam, Who does? and I apologize for
sending you my post yesterday, It was not intended for you. But at least I
did it politely.

---
Grudgingly offered apology accepted.
---

My advice to you is to settle down, All this high tension is bad for
the old ticker.....

---
I don't want your advice, but thank you for being concerned.

BTW, what do you have against bottom posting?


--
John Fields
Professional Circuit Designer

 

[Pat Ziegler]

"John Fields" <jfields@austininstruments.com> wrote in message
news:ndf3c1pju332hvnisrngqglrasrega4a7o@4ax.com...

On Tue, 28 Jun 2005 15:46:17 -0500, "Pat Ziegler" <pzig@weisd.com
wrote:

John:


I am not dodging anything.

My point is that you fly way too far off the handle. You use rude &
foul language in a public forum yet you seem to hate me because I had
the
gaul to advertise my business in this forum. So, I can't invite someone
to
visit my website but yet you are free to rant and rave all you want.

---
I certainly don't hate you, and I haven't criticized you advertising
your business in this or any other public forum, I criticized your
sending me SPAM via private email and then defending the action rather
than offering an apology. I am abrasive on occasion and I use foul
language whenever, in my opinion, it's warranted. YMMV. You're free
to do whatever you want to here, but you need to be aware that if what
you do pisses people off you're going to hear about it. Welcome to
Usenet.
---

I have no problem with your correction, In the end I think my
suggestion to purchase a gas powered compressor is the still the correct
answer. Why buy a generator to power an electric compressor when they
make
gas powered compressors? Seems simple enough to me.

---
Because he already has a compressor and if he gets a generator he can
use the generator for other things if he wants to?
---


I understand you do not like spam, Who does? and I apologize for
sending you my post yesterday, It was not intended for you. But at
least I
did it politely.

---
Grudgingly offered apology accepted.
---

My advice to you is to settle down, All this high tension is bad for
the old ticker.....

---
I don't want your advice, but thank you for being concerned.

BTW, what do you have against bottom posting?


--
John Fields
Professional Circuit Designer

John:

Didn't think you would take the advice lol....

Nothing against bottom posting.... Didn't know it was considered bad
form to top post.........

Because he already has a compressor and if he gets a generator he can
use the generator for other things if he wants to?

I thought the compressor he has was too small for the generator. Might
as well put the money into a gas powerd compressor if you gota spend it.


Grudgingly offered apology accepted lol... one tough cookie...

Long day, I going to have a beer. They do drink beer in Texas?

Pat Ziegler
Wholesale Elecrtoincs Inc.
www.weisd.com

 

[John Fields]

On Tue, 28 Jun 2005 17:18:27 -0500, "Pat Ziegler" <pzig@weisd.com>
wrote:

I thought the compressor he has was too small for the generator.

---
Just backwards.
---

Long day, I going to have a beer. They do drink beer in Texas?

---
Yup!

--
John Fields
Professional Circuit Designer