Can a 10 Watt Globe be Powered by 24V?

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Discussion Overview

The discussion revolves around the feasibility of powering a 10 Watt energy-efficient light globe, typically designed for 240V, using a 24V supply. Participants explore the implications of voltage, current, and frequency on the operation of different types of light globes, including incandescent and energy-efficient models.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions whether a 10 Watt globe can be powered by 24V and suggests using higher current to achieve this.
  • Another participant points out that the resistance of the globe is fixed, leading to a discussion on the relationship between voltage, current, and resistance.
  • A participant explains that the current drawn by a device depends on its supply voltage and impedance, indicating that a voltage conversion is necessary to match the globe's requirements.
  • Questions arise about the significance of frequency (Hz) for the operation of the globe, particularly regarding the use of DC motors.
  • Clarifications are made that incandescent lamps do not require specific frequency adjustments, while energy-efficient globes may not function on DC without conversion to AC.
  • One participant expresses interest in using energy-efficient globes and inquires about controlling frequency for these devices.
  • Another participant suggests that compact fluorescent globes would not work on DC and recommends using an inverter for conversion.
  • A final query is raised about creating a circuit to convert DC to AC to power the globe.

Areas of Agreement / Disagreement

Participants express differing views on the compatibility of energy-efficient globes with DC power, with some asserting that they require AC while others explore the possibility of conversion methods. The discussion remains unresolved regarding the specifics of powering energy-efficient globes with a 24V supply.

Contextual Notes

Participants discuss the implications of impedance and frequency on the operation of different types of light globes, but there are unresolved aspects regarding the exact requirements for energy-efficient globes when powered by non-standard voltages.

dvn
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Is it possible to light a globe - a normal energy efficient globe of 10 Watt usually powered by 240v or so.

Can the globe be powered if I use 24v and put a lot of amps to power it up? According to the PIE formula (Watt/Current*Volt)

thanks
 
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Hi dvn! :smile:

Perhaps I'm missing the point, but isn't the resistance of the golbe fixed, so that I = V/R, and W = V2/R? :confused:
 
No. Or rather, yes. Let me explain. The currect a device draws depends on its supply voltage and its impedance. You have little control over a device's impedance, that's set by design. So, if you have a different supply voltage, you need to convert that to the device's expected voltage. If you have 24 volts and need to step it up to 240, you either use a transformer if you have AC or use a device called an inverter if you have DC.
 
Thanks Negitron. That is the exactly the answer I needed.

One more question, the light globe have Hz. So what is Hz and what it does?
 
Hz is the abbreviation for Hertz; it is a unit of frequency--it tells you how many times per second the voltage alternates. For an incandescent lamp, it doesn't matter since it will work on either AC or DC (it's included anyway because it's a standard parameter on electrical labels) but for equipment with motors or transformers the frequency is important. In the US, the power frequency is 60 Hz; in Europe it is 50. Aircraft use 400 Hz, because at higher frequencies, transformers can be smaller for a given power-handling capability. Railroads use 25 Hz for historic reasons.
 
So if I use the DC motors to power up the globe then I need to adjust the correct Hz for the globe?
If that is so, how can I adjust the correct Hz?
 
You don't need to. Incandescent lamps don't care about Hz. As long as the voltage is correct, it will work.
 
I understand about the normal old globe will work perfectly but what about those new energy efficient globes. I would like to use those since they use a lot less power than the old globes. Old globes are usually 60W to 100W and the energy efficient globes only use aound 10W. So that is why I asked if it is possible to adjust the Hz or a way to control Hz.
 
Oh, are these compact fluorescents? No, those won't work on DC. If you only have DC available, you'd have to convert it to AC with an inverter. You can buy automotive inverters which take 12 VDC and supply 120 VAC (in the US; presumably 240 V units are available for Europe).
 
  • #10
Ok, if I make my own circuit to get DC to AC from the motor then will the globe work?
 

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