Home » Public Forums » GMCnet » amperage draw
amperage draw [message #160606] |
Thu, 16 February 2012 22:52 |
RadioActiveGMC
Messages: 1020 Registered: November 2010 Location: Hot AZ desert
Karma: 0
|
Senior Member |
|
|
Someone said once that if you add resistance to a circuit amp draw stays the same. Example if you have a 12v motor and it draws 10amp and you'd like to reduce it to 7 amps, adding a resistor (using ohms law not debating that at all) to the circuit would still have the same amp draw. I've scratched my head since I've read it. If you reduce the speed of a motor and it turns slower, amp draw goes down. The resistor would add "resistance" but not draw as many amps as the load would of originally...
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
|
|
|
Re: [GMCnet] amperage draw [message #160624 is a reply to message #160606] |
Fri, 17 February 2012 06:37 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
'someone' was mistaken. Take your trusty meter and give it a try.
--johjnny
'76 23' transmode norris
'76 palm beach
From: Michael <radioactive626@msn.com>
To: gmclist@temp.gmcnet.org
Sent: Thursday, February 16, 2012 11:52 PM
Subject: [GMCnet] amperage draw
Someone said once that if you add resistance to a circuit amp draw stays the same. Example if you have a 12v motor and it draws 10amp and you'd like to reduce it to 7 amps, adding a resistor (using ohms law not debating that at all) to the circuit would still have the same amp draw. I've scratched my head since I've read it. If you reduce the speed of a motor and it turns slower, amp draw goes down. The resistor would add "resistance" but not draw as many amps as the load would of originally...
--
***"Gettin There"-1973 23' Sequoia-
Michael, Casa Grande, AZ
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
|
|
Re: amperage draw [message #160644 is a reply to message #160606] |
Fri, 17 February 2012 09:12 |
RadioActiveGMC
Messages: 1020 Registered: November 2010 Location: Hot AZ desert
Karma: 0
|
Senior Member |
|
|
Ok, I honestly wasn't even trying to open a can of worms. I just really scratched my head maybe I misread it as well. I appreciate the replies. RFburn for a long time I've wanted to say that is the best of the best "handles" for a forum.
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
|
|
|
Re: [GMCnet] amperage draw [message #160656 is a reply to message #160625] |
Fri, 17 February 2012 10:04 |
|
Only applies to AC circuits and has to do with the phase
relationship between Voltage (E) and Current (I) in a
reactive (L or C) circuit (high school and college
electronics 40 or so years ago!)
tt
On 2/17/2012 4:40 AM, Steven Ferguson wrote:
> ELI the ICE man.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Terry Taylor
'74 ex-Eleganza SE
San Lorenzo, CA
http://www.n6mon.org
http://dldesignstore.com
|
|
|
|
Re: amperage draw [message #160670 is a reply to message #160669] |
Fri, 17 February 2012 11:28 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
I have grabbed a few low power (under 100 watts) active antennas in my life. I choose not to think about it, but I sure remember. I'll take 120 VAC over RF any time.
It is kind of like grabbing a spark plug wire. You remember it forever.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
Re: [GMCnet] amperage draw [message #160679 is a reply to message #160670] |
Fri, 17 February 2012 12:20 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
If you grab one of mine, you get fuittd for a box. For eternity. They ain't low power.
--johnny
'76 23' transmode norris
'76 palm beach
From: Ken Burton <n9cv@comcast.net>
To: gmclist@temp.gmcnet.org
Sent: Friday, February 17, 2012 12:28 PM
Subject: Re: [GMCnet] amperage draw
I have grabbed a few low power (under 100 watts) active antennas in my life. I choose not to think about it, but I sure remember. I'll take 120 VAC over RF any time.
It is kind of like grabbing a spark plug wire. You remember it forever.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
Re: amperage draw [message #160703 is a reply to message #160606] |
Fri, 17 February 2012 16:38 |
g.winger
Messages: 792 Registered: February 2008 Location: Warrenton,Missouri
Karma: 0
|
Senior Member |
|
|
Okay,,,,heres how this works. Motors have maximum torque and maximum current at 0 (zero) rpm,s. Thats why the lights dim when you start a motor,,,, no RPM's. Now if yoy put a meter on a motor when its not running its almost no ohms. Its just copper wire ,right??? So how come its not alot of amps when running???? When a motor spins, it has copper wire passing thru a magnetic field. Remember,,,,,,this makes a voltage. Like a generator!!!! This voltage "bucks" the voltage that drives the motor. Oposite polarity!!! CEMF ,(counter electromotive force.) So the running current is limited by CEMF. When you cut the voltage with a resister that slows the motor and the "resistace" of the motor changes because of less "CEMF",,,,,, bad juju. Or overheating. The resistance of the motor goes down and changes the resistance of the series circut. Fan motors on GMCs are built for this. The resisters are HD and cooled by blowing air. Use pulse width modulation instead. (on/off quickly,,,like 50 times per second). Hpe this helps,,,,,,PL
78 RB Royale
Hubler conversion,galv. frame
Caddy 500
Still no dash
|
|
|
Re: [GMCnet] amperage draw [message #160753 is a reply to message #160679] |
Sat, 18 February 2012 02:20 |
Ken Burton
Messages: 10030 Registered: January 2004 Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
Johnny Bridges wrote on Fri, 17 February 2012 12:20 | If you grab one of mine, you get fuittd for a box. For eternity. They ain't low power.
--johnny
'76 23' transmode norris
'76 palm beach
|
I realize that. That is why I'm extra careful working around or on Commercial towers.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
Goto Forum:
Current Time: Thu Oct 24 23:28:22 CDT 2024
Total time taken to generate the page: 0.01221 seconds
|