## dummy load for power supply testing

3. These dummy load attenuators can get very pricey. Working mode: Load step control Total testing capacity ranges from 0kw to the max consisting of 10kw, 20kw, 50kw, 100kw load setting switches plus a 0-10kw fine-tuning knob. The DLU is a building block that can be replicated to any level as required. Load banks are connected to electrical power supplies to simulate the supply's intended electrical load for testing purposes. EEVblog August 1, 2010 EEVblog, EEVblog - Podcast Comments Off on EEVblog #102 – DIY Constant Current Dummy Load for Power Supply and Battery Testing 43,607 Views Dave grabs a few junkbox parts and builds a useful constant current load for switch mode power supply, battery testing, and other applications. Report. 4. The collector of an NPN transistor behaves like a current sink so it has a very high internal resistance. Testing power or external utility power supply for fans. It is a commercial unit, and unfortunately the ceramic power resistors I can get on eBay do not physically fit the machined mounting. You can find lots of DIY dummy load projects and we won’t be talking about commercial ones right now. One of the best ways to test any power supply is to use a dummy load made with bipolar NPN transistors. Well, Dummy Load is the equipment that commonly used for draws power at a known rate (They also known as a ‘large resistor’). Load banks are devices with dummy loads, specifically designed for battery discharge testing or testing of power sources such as battery chargers, uninterrupted power system or generators. To demonstrate this, we will use a 7805 linear voltage regulator to step the 12V supply down to 5V, and draw an increasing load … This variable dummy load is helpful in power supply testing by providing virtual load which can be adjusted to draw certain current. A very small low-power dummy load such as a ceramic power resistor or 10-watt light bulb can be attached to the supply to allow it to run with no primary load attached. I want to make something that will properly load all lines so I can measure voltages and ripple of old power supplies and on that way determine if they are stable, accurate and have ripple under ATX standards. Users can set adjustable load power within rated power. So I needed a new 50 ohm load. A nice dummy load. My old boss built a 6kW dummy load for testing a generator by winding galvanised fence wire around a 4inch asbestos drain pipe in the early 1960s. \$12V \times 8A = 96W\$ so I guess it should be good for about 80-85W . Follow. This dummy-load circuit has been in use at Maxim for more than 10 years (see the figure).It's useful for testing power supplies and power amplifiers as well as drivers for LEDs, relays, and solenoids. An RF power meter and frequency counter will also be useful, although if your receiver has a digital frequency readout and S-meter, the latter two items are not really necessary. Multiple units can be paralleled for larger current draws. It has great practical benefits, such as simple and low-cost construction, reasonable power dissipation, negligible leakage inductance, and … 60KW DC Dummy Load Bank For Power Supply Testing . Of course that was before the dangers of asbestos was known. Auto measuring phase voltage, line voltage, three phase current, power factor, frequency, load duration etc. To test whether the SMPS is alive, I plan to put a dummy 10ohm 10W load across one molex connector. 1.2. A month ago, while testing the transmitter’s power supply (capable of sourcing 200 watts) into my best 50 ohm RF dummy load, I burned out the ceramic resistor . Depending on what the switcher chip in the supply is , the supply can shut itself down if the output voltage goes high. A load bank (dummy load) is a stationary or mobile piece of equipment that provides operator-adjustable electrical resistance or resistance and reactance to simulate the actual electrical load the genset is intended to power. Most of the supply voltage will be dropped across the resistor, and the energy contained in the supply current is normally dumped as heat. Main Functions and features. resistance dummy load for generator sets testing Main functions and features: 1. Select a dummy load based on the power supply’s specifications by using Ohm’s Law. Each unit is electrically isolated so they can be arranged to test +- power supplies. Power Electronics: 0: May 29, 2020: D: High side power switching advice. Reading on the internet indicates the SMPS may burn itself out if powered up without a load. 2. Testing Power Converters Using a Liquid-Rheostat Dummy Load Described here is an electrochemical cell that can be a very effective dummy load for testing power converters. You could use a piece of salt glazed drainage pipe as the former and wind the fence wire until you get the correct resistance. From 0kw to the max, any load combination is achievable. If you are testing various power supplies (switching or traditional), surely you will need a test load, whose current consumption can be regulated. Nick found out that most DIY dummy loads tend to be complicated or unavailable. Main Functions of 5kW Rack Mount Load Bank for Data Centre Dummy Test (1) Load Test: User can load any power within rated power, and test the output capacity of under test power supply. For \$10 \Omega\$ \$10W \$ load: The first version (v1.0) of my USB Dummy Load circuit presented here is a cheap and cheerful solution for testing USB chargers and USB power banks/batteries. The latter basically being the former with a way to tap off a highly attenuated signal, to feed a Spectrum Analyzer, for example. Post subject: Choosing a dummy load for testing a new power supply design. I used a "selector switch" from Idec to allow selection of 4 ohms (two resistors in parallel), 8 ohms (4 resistors in series-parallel), or 12 ohms (one in series with two in parallel). EEVblog #102 - DIY Constant Current Dummy Load for Power Supply and Battery Testing. For this reason, it is best to provide a dummy load resistor to one of the power rails to ensure a stable, continuous supply of power … resistance dummy load for generator sets testing PF=1; resistive load:500kW; 400VAC, 50Hz, 3phase 4wire. The current of dummy load freewheels through the closed contactor. Since the test works at a low power state, which is less than the short-circuit capacity of power supply, so the impact of short test can be ignored. 10 years ago | 51 views. Kaixiang has more than 20 years of professional experience in testing and commissioning of generators, batteries and UPS. The simple design uses power resistors to insert a load on the USB power lines, imitating an external device drawing a delimited amount of power from the concerned USB port. Self-Powered Dummy Load Checks Out Multiple-Output Power Supplies This spartanly simple, adjustable, active current load for the 20-mA to 20-A range is powered by the very current it controls. General Electronics Chat: 10: May 12, 2020: DIY high current power supply from car alternator: Power Electronics: 12: Apr 20, 2020 Any loop instability will be uncovered this way. Such a dummy load can help you to find out exactly the current threshold, where the ripple starts to occur, the current limit kicks in, the output voltage start to fall or the electronic fuse turns off. You don't even need a control loop in the dummy load, just thermal runaway compensation. For example, a power supply that’s rated for 10 volts and 1 amp needs a resistor of at least 10 volts times 1 amp = 10 watts. Without a load, it may shut down. 1,Through combination the discharge power switch can setting the discharge power.. 2, LED meter can display voltage and current.. 3,Power consumption componnets adopts special alloy resistors.. 4,Cooling type: forced air cooling.. 5, with wheel castors at the bottom of the enclosure. You can use this dummy load to simulate the load on the power supply circuit under different load conditions, to monitor the temperature curve in relation to load. 2. Also known as a DC programmable load, these AC or DC electronic loads are used by power supply, battery, solar, wind, or other manufacturers who want to thoroughly test their power sources. It means that this USB power adaptor can not supply 62mA at 5V but just can at 4.7V! The SMPS lay unused for nearly 10 years now. Configurable specifications: total power rating, load duration, memory interval, time etc. The dummy load can be a power resistor rated to handle the supply’s maximum output. If you dont have a load, the output voltages will rise above their nominal values. I don't want to spend big on a programmable load, something basic, even quite Heath Robinson would be adequate, but I would like to dissipate 60V at 50 Amps for say an hour, so water cooling looks promising. Hi I'm reading up all the various youtube videos, websites, etc on converting a surplus PC ATX power supply to be a benchtop supply, and all of them note the ATX requirement for a dummy load between 5V and ground or the PSU will turn off. 1.1. An electronic load is a type of instrument that applies a voltage and sinks current. Even so, it may or may not be stable. I've been building audio amplifiers for years. Now the dummy load just support CC (Constant Current) mode now. The power supply charges the dummy load to a certain current until flattop, then close the contactor to short and turn of the SCCPS. How to make dummy load for ATX power supply 300W Is there any schematic to build power supply load to test 300W power supplies? ATX supply needs a minimum load on its output to regulate. Some ATX PSUs will supply power to the outputs without a dummy load resistor. Joined: 23 May 2013 2:53 am Posts: 47 Location: Yorktown, VA I'm modifying an existing circuit, a tube-based guitar amp, and I'll be using a new transformer, a new level of desired B+ voltage, and a totally new rectifier arrangement. Power Electronics: 0: May 20, 2020: C: Is a 500w switching power supply enough for a 400w motor at high draw+additional power supply questions. Testing reports of "load at permanent power rating", "load at certain power rating", "Sudden increment or … With manual controlled variable loads, the load banks assist in the stimulation of actual loads to test and prove the design, performance and the capacity of the system. The Dummy Load Unit is an active power supply load that can be adjusted with a multi-turn control. Dave grabs a few junkbox parts and builds a useful constant current load for switch mode power supply, battery testing, and other applications. we set the target constant current 59mA(about 60mA), for a while the load stabilized, and see the sample I/V, we find that now the current trough the dummy is 62mA, but the voltage is drop to 4.731V !! A good design of dummy load can be found in the project A Switched Dummy Load, also in this book. I think I would find a "dummy load" for testing power supplies useful. Posted: 28 Jul 2014 10:37 pm . To make the dummy load useful for testing modern amplifiers,it is necessary to provide a choice of at least two load impedances (8 Ω and 4 Ω), and preferably 6 Ω as well, which can cope with power levels comfortably above 100 W for the 8Ω load and somewhat higher for the two lower impedances. I bet you face lots of problems in design process where you simply need to test power supply, or LED by providing/drawing constant current regardless to voltage change. Such device is called a dummy load. Load step resolution is … These are nice metal-tubbed power resistors made by Milwaukie resistor. 4. EEVblog. If you’re going to be building and testing amplifiers, you’ll need a high power dummy load or attenuator.