I'm not quite sure a standard DC load will do what you want because the control loop will always lag behind and could mess with the control loop of the system you are testing. For this kind of tests I designed & build a switched resistor DC load myself. I can set it to a specific resistance and because its purely resistive it will keep that setting no matter what appears at the input.
Well, we normally run DC motors in automotive and heavy duty applications so this isn't a lightweight system. I think we would normally run CC or CR mode for most tests but some could be upwards of 800W. I believe this can be achieved by paralleling the devices in CC or CR mode. Some re-brands state they can be paralleled but I didn't recall seeing anything in the Array manual about it.
Voltage: 12V/24V nominal but some tests can be at 28V.
Current: ~10-15A but some tests may require almost 30A
Wattage: Most tests are done at 12V so we could do most of it with ~400W but if the parallel combos work, then we can get up to the ~850W for the extreme tests.
PWM Frequency: 5kHz-20kHz
Filtering: What type of filtering are you asking about?
I guess a lot depends on the current slew rate but the manual states 1mA/us~4A/us on CCH mode which is quite a range so not sure what the driving factor will be.
The transient generator can handle up to 50kHz so I would expect it could handle a PWM source upwards of that frequency as well.
Thanks for the feedback.
Mike
I'm not quite sure a standard DC load will do what you want because the control loop will always lag behind and could mess with the control loop of the system you are testing. For this kind of tests I designed & build a switched resistor DC load myself. I can set it to a specific resistance and because its purely resistive it will keep that setting no matter what appears at the input.
That is what I did for my setup. Resistors and capacitors are dumb and predictable. I have an ARRAY DC load, but I am looking at a Chroma mainframe so that I can automate with LABView.
Well, we normally run DC motors in automotive and heavy duty applications so this isn't a lightweight system. I think we would normally run CC or CR mode for most tests but some could be upwards of 800W. I believe this can be achieved by paralleling the devices in CC or CR mode. Some re-brands state they can be paralleled but I didn't recall seeing anything in the Array manual about it.
......
Filtering: What type of filtering are you asking about?
My experience is that a DC load doesn't really like a dynamic power source. For instance, to illustrate I hooked my Array load up to my Rigol Power Supply, and set the load to constant resistance mode, and set the rigol to deliver at most 1A at 24V. See the video below to see what happens..... in short the load can't adjust correctly with this type of power source - it keeps trying but it doesn't succeed.
Here's a little more about applying PWM to an Array 3732A load.
Here's a little more about applying PWM to an Array 3732A load.
As far as I can tell, there is no such thing as an Array 3732A load. What is the correct part number?
Here's a little more about applying PWM to an Array 3732A load.
As far as I can tell, there is no such thing as an Array 3732A load. What is the correct part number?
I've just got an ARRAY 3721A. I'm quite impressed with it so far but I'm a bit surprised by one design decision. Peeking under the heatsink assembly, I could see eight pass transistors in what looks like a TO220 packages to me. Granted, the heatsink is beefy, there are two fans and the airflow is tunneled within a metal sheet shield but isn't asking the poor TO220s to dissipate 50W each maximum (the unit is rated 400W) stretching it a bit? I'm pretty sure they knew well what they were doing but still, why not TO247?I could imagine the thermal compound going bad on one of them and the heatsink-mounted temperature sensor not even noticing as the localized hot spot from a single TO220 wouldn't affect the average heatsink temperature much. Or am I overthinking it?I realized the last sentence didn't make much sense but anyway, seems quite strange to use TO220 in such device.
Hello all,
I came across this thread while googling for a manual for a Kikusui PLZ300W electronic load. I need an electronic load for a project I took on, and am on a tight budget. I looked at the Array units and they seem nice. I ended up buying the PLZ300W, on ebay, for $360US, including expedited shipping.
My main reason for making this choice was budget, and, in a previous life, I shared an identical unit with a couple of engineers and a couple of techs. I was in that lab for ten years, and that load was no spring chicken when I got there. It performed flawlessly for all the time I was there, and it was in high demand (lab was engineering department for a battery and charger manufacturer).
I didn't over-think it, and went with what I know. I doubt it has the features many of you seek, but, as far as dependability and accuracy per dollar, it's a worthy consideration (if buying used).
I think we all love new gear, but I've been so burned by Chinese made goods, I generally do what I can to avoid them. It may seem racist but, really, I've thrown away A LOT of Chinese made tools; frankly, I think there is some cultural differences, and they do not embrace the meaning of the word "quality" in the same way. Regardless, I did just buy that 1052E.
I don't do much engineering these days, but have this one job, and need to set up a mini lab at home. I'm trying to do it for under $1000US, so as not to suck all the profit out of the job. I bought a Rigol 1052E direct from the manufacturer, two HP bench supplies (6289A, 6291A), and the PLZ300W, and, so far, with shipping, I've spent $833US. I still need a simple, low-speed function generator, and an array of test leads, but I think I'll make my budget. Considering that I've not been watching ebay for good prices, let alone hit up the HAM radio folks, but rather selected and purchased these items today, at the "buy it now" premium, I think one could do even better.
Anyway, my point is, 30 year old equipment doesn't tend to inspire confidence, and usually lacks great, modern features, but the old thru-hole gear is very dependable and very repairable. Best of all, you can choose quality levels you couldn't otherwise get into the budget. The one caveat is the dark years of electronics: the previous decade. When Europe introduced the RoHS and WEEE legislation, it all really went bad. The lead free solders, tin whiskering, delaminated PCBs (from the higher heat for new solders) made for some of the worst lived electronics in the history of, well, electronics! I avoid gear from that era, whether it be an electronic load, or a car stereo. You can keep it
So, there are some opinions from some random guy on the internet.
Best of luck in your endeavors.
Regards,
Mike O'