Hello all,

I need to run a 12V/0.6A dc fan to cool the MOSFETs of an inverter with 1kV input. it would be overkill to use some power supply to step down the 1kV to 12V or any DCtoDC converter!..
I thought of using just a resistor divider to step down the voltage to an acceptable range to use a voltage regulator but I am not sure about the idea! is it feasible?

is there any better solution?

Regards,

 

Using a resistance, or any linear voltage reduction method from 1KV to 12V 600 mA would need to dissipate nearly 600W as heat. This is a ridiculous thing to do. And a DC to DC converter with 1KV inout would not be easy to do.

There s no practical way to do this.

Is there no other power available? If not, the only reasonable solution is a battery.

 

Using a resistance, or any linear voltage reduction method from 1KV to 12V 600 mA would need to dissipate nearly 600W as heat. This is a ridiculous thing to do. And a DC to DC converter with 1KV inout would not be easy to do.

There s no practical way to do this.

Is there no other power available? If not, the only reasonable solution is a battery.

Thank you Bob for the guidance,
In that case, I will just use an external power supply.

 

Hello all,

I need to run a 12V/0.6A dc fan to cool the MOSFETs of an inverter with 1kV input. it would be overkill to use some power supply to step down the 1kV to 12V or any DCtoDC converter!..
I thought of using just a resistor divider to step down the voltage to an acceptable range to use a voltage regulator but I am not sure about the idea! is it feasible?

is there any better solution?

Regards,

What is the inverter output voltage? If that were 12 volts the solution would be simple. If it is 120 volts or 240 volts, fans running on those voltages are available. A resistor to drop the voltage is the worst possible method. An added 12 volt winding on the inverter transformer will be the very best option. It should not take very many turns of quite thin wire, and then just a diode bridge.

 

There are DC-DC converters available off the shelf, like this one:
https://www.digikey.com/en/products/detail/mornsun-america-llc/PV15-29B12R3/17883299
Full search here:
https://www.digikey.com/en/products...NVATCMQJzcAsnIAXWIAHAC5QQAZVEAnAJYA7AOYgAvuqA

 

Resistor dividers should not be used to reduce a 1kV voltage to power a 12V fan due to their inefficiency, power wastage, and the need for high-value, large, and expensive resistors that generate significant heat. Instead, a better approach is to employ a DC-DC converter, which is far more efficient and available in various sizes and power ratings.

Several DC-DC converter options are suggested, such as the Mean Well RS-50-12 for most fan applications, the Traco Power TEN 30-12WI for higher-power requirements, and the XP Power MYB-10-12 for smaller, lightweight applications. Many other converter choices exist, so it's crucial to select one tailored to your fan's needs in terms of size and input/output voltage range.

 

Based on the need to cool transistors, this is not a commercially made inverter, but a special design, built for some specific application. So if that is indeed the case, probably the inverter transformer also is a special case design. In that case it will be both cost effective and also the simplest possible solution to add another winding to the inverter transformer to provide fan power. No additional regulation would be required, so not much filtering either.
Of course it may also be hat the inverter is boosting the voltage, not reducing it.
We have no information about the inverter power or voltage, current draw, nor power level.
So my guess wins.