What is the most convenient load for dynamo test-rig being designed for low-power motors?
We are designing a dynamo test-rig for low-power motor and comparing different types of load. What are you using? What are their pros and cons?
We use AC servomotor from Mitsubishi Electric equipped with an incremental position encoder. This motor is controlled using the MR-J4-200, an AC servo amplifier. It provides flexible control an can oberate in motor and generation modes. However the maximum speed of this servo motor is limited with 2000rpm, thus it may not fit all motor drives.
Sangtaek Lee These links might be useful:
1. https://www.powertransmission.com/blog/force-control-dynamometers-suitable-for-high-torque-low-speed-testing/
2. https://www.electronicdesign.com/power-management/whitepaper/21127182/simple-lowcost-dynamometer-setup-for-motor-testing-part-1
Eddy current brakes are usefull for dynamic loads and load steps. Depending on the speed range, any type of motor / generator can be used as long as the control loop can control the torque. induction motors with a bi-directional drive can be cost effective and the frequency is limited by the shaft bearings mainly. If speeds in excess of 5000 rpm is needed, transmissions or servo motors may be more suited. I guess the question lies in the complexity required and the cost limits. Motors with drives can put the energy on the grid whereas other types like eddy current brakes or alternators need loads with cooling i.e large resistors.
For a very simple case, have the load control the speed and set the torque by increasing the power on the drive motor / machine. For combustion engines, this means change the throttle position.
Anton Dianov Can you provide more information? We are going to design a new dynamo, so we will appreciate your help.
We use powder brakes from Magtrol and one powder brakes from small Japanese company.
If you want to save time I suggest using Magtrol, however if you have limited budget consider brakes from small companies
Tae-Ho Yoon Agree. We tried several brakes and Magtrol was the most convenient. However the cost is high. If you use smaller companies you can save the money, however you may face the problems in delivery and service.
I think, that small companies produce quite competitive brakes. Thus you may significantly save budget. However delivery time can be long, therefore I suggest to think about it in advance.
I also want to point out reliability problem. Typically, brakes are air-cooled, thus you should be careful, otherwise it can be melted.
Wonkeong Kim Please check: https://www.magtrol.com/product/brake-clutch-selection/
Seungmoo Lim To my experience the popular brakes from famous companies can be in stock, so the delivery time is fast.
Sangjoon Lee I agree. Typical delivery time from small companies is about 8 weeks. However, if the model is not popular, they may produce it only after ordering.
Guys, what can you suggest for dynamo needed to test the propeller drive?
I suggest not to save the money and use the most convenient solution. Remember: "penny-wise and pound-foolish"
Young-Kwan Kim The budgets are typically secrets. However, if not, it can help us to help you.
Sangjoon Lee Agree. Sometimes saving money results in deadline violation and additional costs. Think twice!
Anton Dianov Making a table takes a lot of time, so many people hate it. However, it helps to analyse the data and simplifies selection.
Anton Dianov I understand. However we ask to disclose only part of it, so it may be not a secret.
There are many different types of loads that can be used for dynamo test-rigs, each with its own advantages and disadvantages. Some of the most common types of loads include:
- Resistive loads: Resistive loads are the simplest and most cost-effective type of load. They are also the easiest to control, making them ideal for testing motors with variable speed and torque requirements. However, resistive loads can generate a lot of heat, which can be a problem if the test rig is not properly cooled.
- Eddy current loads: Eddy current loads are more expensive than resistive loads, but they are also more efficient. They do not generate as much heat, which makes them ideal for long-term testing. However, eddy current loads can be difficult to control, making them less ideal for testing motors with variable speed and torque requirements.
- Hydraulic loads: Hydraulic loads are the most expensive type of load, but they are also the most accurate. They can be used to simulate the real-world load conditions that a motor will experience in use. However, hydraulic loads are also the most complex to use, and they require a lot of maintenance.
The most convenient load for a dynamo test rig depends on the specific needs of the test. If the test is simple and does not require a high degree of accuracy, then a resistive load may be sufficient. However, if the test is more complex or requires a high degree of accuracy, then an eddy current load or hydraulic load may be necessary.
Ultimately, the best type of load for a dynamo test rig depends on the specific needs of the test. If you are unsure of which type of load to use, consult with a test engineer or a motor manufacturer.
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