I used your measurements to generate my empirical equation to try to get a close curve-match to your data.

LOL! That explains things, alright.

I seem to remember an earlier thread, several years ago, where we were talking about the characteristics of tungsten incandescent lamps but I can't remember the context.

 

Very true.
Does it have terminal blocks on the back for anything other than the output?

That is how it looks to me. One large screw-terminal output, and a row of 11 strapped alphanumerically-labeled, smaller terminals for controls other than the front panel.

 

That's only true of the bulb is rated for 12V, 100W.
A 100W, 120V bulb will have a hot resistance (at 120V) of 120²/100W =144Ω and a much lower cold resistance.

Below is the simulation of an incandescent bulb using an empirical Spice model.
It shows that a 100W, 120V bulb will draw about 270mA @ 12V.

View attachment 198361

I tried the light bulb connection, and got the results I was hoping for. It was a 250 watt bulb, and as soon as I switched things on and started to crank up the voltage from zero, the light glowed, but the power supply buzzed loudly, so I ran it back down to zero. But I had seen the ammeter register the event, so I know that it at least works.

 

That is how it looks to me. One large screw-terminal output, and a row of 11 strapped alphanumerically-labeled, smaller terminals for controls other than the front panel.

You need to find out what those connections are. Some may need to be connected and some may need to be not connected. No way to tell without instructions.

 

Hello,

Perhaps you can give us the typenumber of the powersupply.
There might be an possibilty to find a manual.

Bertus

 

I think I can make out Harrison, so you will likely find it under the HP number. HP gobbled up Harrison Labs.

 

It's similar to mine I have a 6434 b which is 25 amps I believe his 6433b both are obsolete but definitely doable I did I hope this helps

 

It's similar to mine I have a 6434 b which is 25 amps I believe his 6433b both are obsolete but definitely doable I did I hope this helps

If it's like that check section 3.6

 

I needed a decent lab power supply, so I bought a used HP 10-amp PS

You bought yourself a little gem
After calibration you can run it 24 hours a day, I ran for a month straight 20 amps they are built like tanks and will destroy your load before harm comes to your power supply.

 

A quick method to set the current limit of a power supply like that is to set the voltage to a low setting (~1 volt is fine) and short the output. This allows you to adjust the current limit to your desired setting. Keep in mind that the wire that you use to short the output must be capable of handling the current you will drive through it. 30 AWG wire will melt before you turn the current up very far. For a 10 amp supply, 18 AWG will work for a short while. You may notice it getting warm if you leave it set at 10 amps for more than a few seconds. Once the current limit is set, remove the shorting wire and set the voltage to your desired setting.

To determine the accuracy of the current setting would require buying high wattage low value resistors to use as loads and measuring the current at different voltage settings. With analog meters like that, the precision of the measurement is pretty coarse. To test your supply, I'd just make sure that it can supply 10 amps and that it's not varying while supplying that current.

Thanks for the description. The Power Supply is rated at 10Amps and 30-40 DC volts. I assume that means that any amp draw over 10A will cause a problem(?). And I do have the HP-Harrison manual for my particular power supply. I've been running into some terms with which I am unfamiliar, e.g., "current limit". Does that mean that if I crank up the amps on the front panel of the PS, e.g., to 7A, the throughput will top out at 7A, and not go past it to 10? Same for voltage? It sounds obvious, but I don't want to take anything for granted.
Another quickie: I notice that some newer power supplies and step-up and -down convertors can output Constant Voltage and Constant Current. Both types of power have specific uses, in welding, LED power, and battery charging. Is this just a recent technological expansion of Voltage Regulation into Current Regulation, and are there any other general uses for those types of power?

 

Does that mean that if I crank up the amps on the front panel of the PS, e.g., to 7A, the throughput will top out at 7A, and not go past it to 10? Same for voltage?

You got it.

I notice that some newer power supplies and step-up and -down convertors can output Constant Voltage and Constant Current.

They are the same as your supply.
They can operate constant-current or constant-voltage depending upon the load, and the the current and voltage settings.
The supplies are constant-voltage until the current-limit is reached and then they are constant-current.

 

I've been running into some terms with which I am unfamiliar, e.g., "current limit". Does that mean that if I crank up the amps on the front panel of the PS, e.g., to 7A, the throughput will top out at 7A, and not go past it to 10? Same for voltage? It sounds obvious, but I don't want to take anything for granted

the following is the same difference another way of looking at it.
CV: the output voltage is constant while the output current will change with the load.
CC: Constant Current
The output current is constant while the output voltage will change with the load.

 

I can't add much more to crutschow and Delta prime's comments, except to note again how I used a similar supply to drive an LED at constant current. Once the LED current was set, the voltage setting simply needs to be a little higher than the LED forward voltage which can be found in the specs/datasheet of an LED. The voltage might vary but the power supply will keep the current fixed at the level that it was set.

 

Thanks. It all helps.

 

There are subtle difference between CL (Current Limit) and CC (Constant Current). In reality, your setting bounds. A fuse is one way of setting a bound.

When your in CV, you set the max current you want to draw.

In CC mode, you set the maximum compliance voltage.

With some supplies, you would have to short the leads to set the current and others you can set it independently.

 

When your in CV, you set the max current you want to draw.

In CC mode, you set the maximum compliance voltage.

??

I've been running into some terms with which I am unfamiliar

The TS is unfamiliar with the nomenclature used concerning power supplies nor speaks in the vernacular. I was employing the K.I.S.S method.