Problems With Power Supplies...

[flocktastic]

Has anyone had problems with their DC power supplies?
I'm using a hand held flocker that will work with as little as a 9v battery, up to 15v. At 15v, -20KVDC should be produced.
I started off using a cheap multi voltage power supply (the type that you can switch between 3v and 12v and reverse polarity, current 300mA 5W). This worked fine at 12v for around a year but eventually died.
When I found out that I could use 15v and increase the negative ions, I purchased another switchable power supply that resembles a laptop power unit. I set it to 15v and the current is up to 4A 60VA max.
I figured the higher ampage would mean it would be more robust and last longer. The first unit allowed me to flock for one afternoon. The second time I used it, I lost power half way through a batch of 6 heads. The blue light on the unit had gone out and the mulitimeter said that only 5v was being supplied, regardless of its setting (switchable from 5v to 15v).
I took it back to the shop and got another, thinking maybe I was just unlucky.
The second one lasted for just 2 heads before the blue light went out!

So why are my power supplies dying? Can any of the high voltage back track to the unit and fry it?

Would it be better using a 15v supply with a current of 300mA?

[Ray (Flock Man)]

There may be a newly created leak in or around your HV generator. It happens over time. HV doesn't go by the same rules as normal electricity we use everyday.
I've seen HV leak through the wire coating, that was taped, inside a rubber hose, which was inside a PVC pipe. I've witness this leak in my shop.

The wire of your device may be HV wire, but at what rating??? This is the question. Was the expensive 30kV rated or higher wire used or is it a 10kV rated or less.

Say, your unit is made to run at 9 VDC in and 15kV out you could get away with lower rated wire because it never really gets strong enough to do it's own thing and escape. When you get up to 20kV the HV wants to get loose. Off a 9 volt battery you may never see an issue because you're basically using an eye dropper to pour water down a funnel. Then using a 15 VDC input you've stepped up to quickly pouring a 5 gallon bucket of water through the same funnel and it's going to spill.

It's not a scientific example, but you get the picture.

You may have to purchase higher rated wire and re-wire it.

This is basically why the high end commercial units are so expensive. They run at much higher voltage so the parts at rated as such.

It's not the fault of lower end models or homemade models. These are made for smaller tasks (like flocking some static grass or a GIjOE head) Flocking these is a bit more about technique and less about higher volts.
Higher volts are better depending on the project. Flocking a blanket verses a penny and so on.

Ray
Flock Concepts