Motor & Battery: 12V 3.5A/hr Support 120V 4.7A Motor?

In summary, a 12V 3.5 amp-hour battery will not support a 120V 4.7 amp motor. It is recommended to use a 120V battery with at least 5 amp-hours for 1 hour of backup supply. Even with a voltage converter, the battery would not last more than 4.5 minutes. A 3.5 amphour battery is not designed to handle such high amperage. Sealed lead-acid batteries and NiCd packs may be able to handle 50 amps, but not for a significant amount of time. Most big commercial/industrial motors are synchronous AC, while small motors in domestic electrical equipment are non-synchronous AC.
  • #1
snaz_86
7
0
1) will a 12v 3.5amp/hour battery support a 120v - 4.7 amp motor? if not kind of battery specifications will.

2) Is an electric motor a DC or AC.

help is much needed,thank you.
 
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  • #2
No. It wont. But by voltage conversion, inbetween by transformer, you can.
better to go for 120V battery with 5 Amp/hr so that atleast for 1 hour u ll get backup supply.
 
  • #3
Even with a voltage converter, 4.7 amps at 120V would convert to 47 amp at 12V (ignoring the inefficiency in the converter). The 3.5 amp-hour battery would go flat in less than 60*3.5/47 = 4.5 minutes.

Of course that might not be a problem, depending on what you want to do.
 
  • #4
It won't even make it 4.5 minutes. A 3.5 amphour battery is simply not designed to handle 47 amperes ever. Think of it like this: I can hold a given weight at arms length for a given amount of time. I can hold a twice that weight at arms length for a shorter amount of time. But it is unlikely that I can ever hold 1000 pounds at arms length no matter how short of a time. I'm simply not built to handle it.
 
  • #5
It might - a jump-start battery can handle quite a bit for a few seconds. 3.5Ah would be unusually small for one of those though. For example, this one is 9Ah: http://hitches4less.stores.yahoo.net/stcoeljustsy.html [Broken]

Whether or not that would be useful depends on what the OP is trying to do...
 
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  • #6
You can get sealed lead-acid batteries down to 12V 1.3AH. They would certainly bang out 50 amps or more, but not for long.

Probably even a 12V NiCd pack would manage 50A if you short circuited it (but don't try that at home!)
 
  • #7
The battery probably won't hold not for any backup time u need like 10 of those batteries to have decent backup.
An electric motor is usually DC driven cause from the way it works, if u put AC current on it, it will move back and forth thus staying in the same place and we don't want that to happen do we ?!
 
  • #8
Actually, most big commercial/industrial motors are syncronous ac. The oscilating induction field drives the motor in sync with it.
 
  • #9
r u sure about that? i mean i know that the engine operates by varying its polarity on 1 side, and keeping it the same on the other. would be difficult to do that using AC, unless you r using a permanent magnet system ? what do u think?
 
  • #11
russ_watters said:
Actually, most big commercial/industrial motors are syncronous ac. The oscilating induction field drives the motor in sync with it.

And most small motors in mains powered domestic electrical equipment (fans, vacuum cleaners, etc) are (non synchronous) AC.
 

1. What is the voltage of the motor and battery?

The motor and battery have a voltage of 12V.

2. What is the capacity of the battery?

The battery has a capacity of 3.5A/hr.

3. What is the maximum current that the motor can support?

The motor can support a maximum current of 4.7A.

4. Can the motor be used with a 120V power source?

Yes, the motor is designed to be used with a 120V power source.

5. How long can the motor run on a fully charged battery?

The motor can run for approximately 1 hour on a fully charged battery.

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