How Can I Power Two Motors with Different Requirements from One 110V AC Outlet?

  • Thread starter Thread starter rolinger
  • Start date Start date
  • Tags Tags
    12v Ac Dc
Click For Summary

Discussion Overview

The discussion centers on how to power two motors with different electrical requirements from a single 110V AC outlet. Participants explore various solutions, including converters and safety considerations, while addressing the differences between AC and DC power calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses a lack of understanding regarding power and electricity conversion rates and outlines the specifications of two motors: one requiring 12V DC and the other operating on 110V AC.
  • Another participant calculates the wattage for the 12V motor as 39.6 watts and suggests using a $5 converter to power it, recommending soldering the wires for a direct connection.
  • A question is raised about whether the calculation for watts is different for AC and DC, with a participant noting a discrepancy in the expected wattage for the AC motor based on its specifications.
  • One participant proposes that the difference in wattage for the AC motor may be due to inefficiencies such as power factor.
  • Another participant advises ensuring that the 120VAC to 12VDC converter has a current rating of at least 3.3A for safety.
  • A suggestion is made to use a dual outlet extension cord to connect both devices safely, with an emphasis on using a power bar with an internal breaker for additional safety.
  • A participant inquires about the possibility of using an inverter to power a 12V winch from household current.

Areas of Agreement / Disagreement

Participants express differing views on the best approach to power both motors from a single outlet, with no consensus on a single solution. There is also a lack of agreement on the interpretation of the wattage calculations for the AC motor.

Contextual Notes

Participants mention potential inefficiencies in AC power calculations and the importance of safety when dealing with electrical connections. The discussion does not resolve the discrepancies in wattage calculations or the best method for powering both devices.

rolinger
Messages
11
Reaction score
0
Hello all. First thing I have to say is I don't understand much about power and electricity conversion rates. But I do have a need to have two different motors, each requiring a different power load, to run off of a single source AC 110 house outlet.

First device: Volts: 12, Amps: 3.3, uses a 12V car cigarette lighter (I assume this is DC power)

Second device is a 2 speed motor: Watts: 37/27, Amps: 0.57/0.39 and runs off of standard 110v AC plug

I am looking for a cheap solution that will allow me to power both devices off of household 110v AC power but really have no idea on to go about doing this since this is my first project I have ever done that requires me to toy with power/electrical sources.

I know I can go buy a 110AC to 12V (cigarette lighter) converter for $5, but that's the kind that plugs into a wall outlet and would require some kind of mickey mouse solution that is unclean and probably not safe. I am looking for a solution that runs off of a single source that feeds both devices. Which means I would need to cut off the cigarette lighter adapter and used the exposed wires to connect directly to this power source.

Also, how do I determine the watt power level of the first device? I need to understand what the total watt power consumption, of both devices, would be.

Thank you for your help.
 
Engineering news on Phys.org
Watts DC = Volts x amps so in your case it would be 12 Volts x 3.3 amps = 39.6 watts.

I don't think you are going to find a device that would supply power for both. I would just go with your $5 converter and solder the wires to the terminals of your machine. Then of course, put plenty of electrical tape. The other machine could just plug directly in.
 
So is watts DC math any different from watts AC ?

Watts DC = Volts x amps (12 Volts x 3.3 amps = 39.6 watts)​

Would the second device simply be:

Watts AC = Volts x Amps (120 volts x 0.57 amps = 68.4 watts)​

The second device "advertises" 37 watts with a pull of 0.57 amps off of a standard 110AC outlet. But the math shows different with 120v AC x 0.57 amps = 68.4 watts. Something isn't adding up right.

Thanks.
 
Last edited:
Perhaps there is an inefficiency such as power factor in the AC device.

Anyway, I'm not sure what you are really trying to do here. 110V Ac is wall power and 12V is a pretty standard power supply. If you the motor and a 12V power supply into a power strip, then you have it all connected together. I'm not really sure what you could do that would be more complex (or useful) than that.
 
When you buy a 120VAC to 12VDC converter make sure the current rating is atleast 3.3A. That's a decent size wall wart. Using a wall wart with that rating is probably one of the safer options you have, especially if you don't feel comfortable with 120VAC circuits.
 
Any time that I've run into a similar situation (quite a few times), I just run a dual outlet extension cord into the device housing and plug the adapter into one of the receptacles. Then a regular cord can be plugged into the other to run the AC stuff. For additional safety, if you're not sure of the power draws involved, use a power bar with an internal breaker.
 
I would like to know if there is an inverter to go from my household current to power my 12 v winch. I have a 4x4 super winch LP 8500 12 v DC 4.5 hp 3.3 kw motor.
 
rolinger said:
So is watts DC math any different from watts AC ?

Watts DC = Volts x amps (12 Volts x 3.3 amps = 39.6 watts)​

Would the second device simply be:

Watts AC = Volts x Amps (120 volts x 0.57 amps = 68.4 watts)​

The second device "advertises" 37 watts with a pull of 0.57 amps off of a standard 110AC outlet. But the math shows different with 120v AC x 0.57 amps = 68.4 watts. Something isn't adding up right.
AC Motors, with few exceptions, look inductive from the ac power lines. The 120v ac x 0.57 amps is 68.4 volt-amps or VA (reactive load).
Bob S
 
Last edited:

Similar threads

Replies
21
Views
3K
Replies
6
Views
4K
  • · Replies 31 ·
2
Replies
31
Views
3K
Replies
6
Views
4K
  • · Replies 68 ·
3
Replies
68
Views
16K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
4
Views
7K
Replies
1
Views
2K
  • · Replies 24 ·
Replies
24
Views
3K
  • · Replies 33 ·
2
Replies
33
Views
5K