AN/VSS-1|3 Power Supply

[modamag]

Guys, I'm in the process of acquiring parts/supply for my next little toy.

I ran accross a company (in the states) that have a stash of Loraine A100F25 Power Supply for pretty cheap (<$250).

Here's the spec on them.

Input Volts 120/208/240
Input Amps : 21/24/38
Input Frequency : 60hz
No . Phase : 1 Phase
Output Votage: 29 VDC
Output Amps: 100Amp
Condition: New/Used? TBD
Misc: High Frequency

According to the listing on ebay, it's adjustable voltage up to 29V and can be use with the VSS 1 or 3.

I'm not a EE guys, so is this unit REALLY sufficient to drive our toy?
Further functionality of this unit would really help.

If any of the VSS owner need one of these power supply let me know.

 

[billhess]

I believe that would work definatly for the 3a. the 1 you might need a battery inbetween cause you are cutting it close. I would doubt if it really puts out 100 amps and a battery or 2 would give you a little buffer.

 

[tvodrd]

Jonathan, billhess has a tested VSS-1 available.

Larry

 

[mattheww50]

I believe that would work definatly for the 3a. the 1 you might need a battery inbetween cause you are cutting it close. I would doubt if it really puts out 100 amps and a battery or 2 would give you a little buffer.

I wouldn't doubt it for a second that it can put out 100 amperes. However the current demands are reversed in the spec, it would be 21 amps at 240V, 24 amps at 208V, and 38A at 120A. So roughly 5000VA in for 2900Watts Out, thats 57%, so the power factor is probably in the mid 60's. That's about right for a big switching supply.

 

[modamag]

So this PS is gonna dump 2KW of heat
But it's enough to power either a VSS1 or VSS-3A :devil:

 

[Xzn]

It'll dump 2kw of heat if it's being pushed to it's full capacity. For example, when my dual core laptop is idle, the power brick is semi cool to the touch. Push both cores to 100% and put the screen on max brightness, the power brick is actually hot.

 

[CarbonArc]

I have a working vss-1 as well.

 

[ShortArc]

The VSS1 startup current will easily exceed 100amps momentarily during startup, so I agree with billhess a set of batteries may be required. Besides heat rejection the blowers in these switch power supplies tend to be very loud so get ear plugs and shades.

 

[mattheww50]

It'll dump 2kw of heat if it's being pushed to it's full capacity. For example, when my dual core laptop is idle, the power brick is semi cool to the touch. Push both cores to 100% and put the screen on max brightness, the power brick is actually hot.

Not going to dump anywhere 2kw heat in the supply. Power= V*I only if V and I are in phase. One of the problems with large switching supplies is they have a very large reactive component, so the voltage and current are not in phase. In the case of a switching supply, V*I on the input side is always higher watts.

This is the reason AC equipment like transformers is rated in VoltAmps rather than watts. If the current is at quadrture (90 degress out of phase), you can still blow a circuit breaker, or burn up wiring because of the current draw, but there is no assurance at all that much actual power consumed in the load.

The power supply is probably about 85-90% efficient, so the heat loss at 2900 watts output is not likely to exceed about 400 watts.

 

[IgNITEor]

Hey everyone. As I was reading through the posts on this power subject, I see that we're getting into switch-mode territory! Modamag, if your Lorain rectifier weighs anywhere near fifty or so pounds, it's not a switching power supply. I've had the aching pleasure of humping the vast Lorain Flotrol line of beast power supplies out of many a telecom shelter. What you have is a FINE source of gnarly, well regulated power. Be careful on tweaking the voltage up too high as this will send the output monitoring board into alarm, and you may have to power-down to reset this.
As with billhess & ShortArc, I would place a beefy truck battery in parallel with the Lorain as well. In the event you accidently (whoa!!!) trip your rectifier off, you'll keep the blower running while recovering that special screwdriver used for voltage adjusting!
Have some great fun with that monster!

 

[BVH]

Revival! As to the adjustability of these, I want to go the other direction - down to 28, maybe 28.5. Is this done by opening up the unit or can it be done externally? Where and what will I be looking for for those that have gone before me?

If it's not a switcher, is it a Linear? I've popped two cheap Mastech 30V/50A PS's, one with a Schottky Diode in-line running ballasted lights. I've been told that switcher's are not a good match for high inductance loads. Can those knowledgeable comment?

 

[larryk]

A little off topic but I bought one of BVH's VSS-3's and noticed a 65 percent increase in brightness going from 24.1 volts under load to 27.5 volts. Anyone else have similar results ?

 

[Norm]

Input Volts 120/208/240
Input Amps : 21/24/38
Input Frequency : 60hz
No . Phase : 1 Phase
Output Votage: 29 VDC
Output Amps: 100Amp
Condition: New/Used? TBD
Misc: High Frequency

Do you think the Amps are reversed? it should draw less Amps at 240V than at 120V.

Norm

 

[larryk]

Yes, the amps are reversed. Here is modamag's post with pictures.
http://www.candlepowerforums.com/vb/showthread.php?198335-AN-VSS-1-and-AN-VSS-3-Power-Supply

 

[IgNITEor]

A little off topic but I bought one of BVH's VSS-3's and noticed a 65 percent increase in brightness going from 24.1 volts under load to 27.5 volts. Anyone else have similar results ?

Yes indeedy. I run the Death Ray at just below alarm level, about 28.4 Volts for the 125 Amp main power supply
and slightly less with the back-up unit. Really likes that 28 Volts! Hot air exhaust pumps out plenty for the chilly fingers.
Most of the telecom grade power supplies, either the big iron units or the switch mode types have the adjustable
pot on the front panel. These were often "tweaked' when multiple units were operating in parallel (for several hundred amps output) to enable safe load sharing.
There was always one master unit working a little harder than the rest :thinking: I'm guessing it was in charge of keeping all the other units operating in fine form.

 

[Phased_Array]

My 3 never came close to the Amps it said it needed, the 1 may be different tho.

 

[nealitc]

My 3 never came close to the Amps it said it needed, the 1 may be different tho.

How much does it actually draw?

Just got my VSS-3 (not A). Considering using a 1500W switch mode supply (Mean Well RSP-1500-27, about $350 new) output 27V at 56A, so I can plug the thing into a 120V/20A outlet. Anyone have any experience using these, or better/cheaper ideas?

Looking forward to some light from my brightest flashlight!

 

[IgNITEor]

nealitc, welcome to CPF and the wild big lights department! Better keep your welding hood close at hand.
I just looked at the spec. page for the model you described. It shows inrush current at 120 Volts requiring a 30 Amp circuit.
If you use a pair of healthy 12 Volt batteries (connected in series for 24 Volts) in the circuit between the power supply and your VSS-3, this will help with starting your light.
Be careful where you "plug" in your power supply. I wouldn't do this with anything less than a dedicated circuit. If you're not certain of this, carefully check out the circuit your considering to use. Not worth the
risk of damaging an existing circuit that cannot carry the load.
If you can, show us some pics of your gear.

 

[BVH]

After frying two switchers on HID lights, and learning that switchers do not like high inductance kickback produced by ballasts, I got a Lorain 29V, 100 Amp rectifier from member Modamag for $150 and haven't looked back. My VSS-3a at only 25.5 Volts, is drawing 58 Amps fully warmed and thru the start and boost cycles. Powering with a full 28 Volts is probably going to kick that figure up significantly as these are not regulated lights. I remember a post years ago by another member showing his military rectifier reading 60 Amps while running his VSS-3.

 

[BravoKilo]

Based on your post to the thread on my AN/VSS-3 and this post, I have been looking at filtering equipment for my light. But I realize something - my ballast is not solid state at all, it is a strip resistor that is cooled from the out flow of the heat exchanger for the light - built into the back of the housing. That being the case, and not having an O-scope, I wonder just how much of a spike I am getting when firing the light? I do not see any highly inductive components in the light at all. Being a DC light, the power factor is not an issue as that is only a function of capacitance and inductance in an AC circuit. My switchmode rectifier does not have a transformer in it so the only other inductance would come from the power to the rectifier itself.

All the same, I do want to protect my gear so I am researching this and designing a power conditioning system that will handle the current requirements of the lamp and I will let everybody know what I come up with. The suggestions you gave to me have really helped, BVH.

IgNITEor - what are you running for your AN/VSS-1? batteries, rectifier, etc? Also, I remember parts of a discussion we had years ago on the playa about your ballast - didn't you have a solid state ballast that you converted back to resistor? That was back in the day when you had your lamp mounted on the back of that trailer if you can remember back that far.