Can I Use a 520A RMS Thyristor for Controlling a 500A DC Motor?

AI Thread Summary
The discussion revolves around the feasibility of using a 520A RMS thyristor to control a 500A DC motor in an electric car project. The original setup involves a 25A thyristor with a zero-cross opto coupler, and the user is exploring the possibility of substituting it with a larger thyristor while considering PWM control methods. A proposed solution involves using a second reverse-polarized thyristor to turn off the first when the PWM signal drops, allowing for controlled motor operation. The user reflects on past experiences with a Jones Chopper circuit that faced challenges due to component quality, ultimately deciding to purchase a 400A Curtis EV controller for better performance. Plans for future upgrades include increasing battery capacity and transitioning to Lithium Ion batteries for extended range.
RJK
Messages
6
Reaction score
0
A while ago I built a pc board that serves as a 3 channel SS relay. The output thyristors are 25A. This circuit uses a zero cross opto coupler to fire the thyristor and turn it off (DigiKey MOC3042). I've used many of these to control aa AC wash machine motor (on/off). The first question is if I could substitute this thyristor (DigiKey Q4015L6) with a big monster one like a 520A RMS (DigiKey ST330S04P0-ND) ?

The second question has to do with controlling the PWM circuit. I think I need to reverse polorize the thyristor to shut it off. If so, then a second reverse polorized thyristor (across the motor)could have the inverted gate polarity with respect to the first thyristor. When the PWM signal drops out then Thyristor 2 reverse polorized thyristor 1 to shut it off and there is no current flow. Then when the PWM comes on thyristor 1 comes on again (T2 now off), and the motor has current. Is this possible to make work?

By the way, this is for my electric car, a 66 MGB.
Roger
 
Engineering news on Phys.org
there's something called a Jones Chopper circuit that uses SCRs and somehow reverse biases them to turn them off. long ago (1979 or 1980), in an electric car project that my school was doing, we built a Jones Chopper, but couldn't get it to work because the capacitors used to help with the SCR reverse biasing, had too much internal inductance (too low of quality). we ended up buying a working chopper circuit.
 
After considring my options, I think I will just buy a 400A, 120V Curtis EV controller. It costs just over $1000. My MG has 9 12V deep cycle batteries (108v), so this should work well. With gas almost at $4.00/gallon, I think it is a wise investment. If my MG does not perform as desired (my old controller and 8 batteries gave me about 20 mile range), I am looking into converting an S-10 or Ranger and I could double the battery payload and should be able to get more than 40 mile range. Eventually retrofit with Lithium Ion batteries and tripple that range.
 
Hi all I have some confusion about piezoelectrical sensors combination. If i have three acoustic piezoelectrical sensors (with same receive sensitivity in dB ref V/1uPa) placed at specific distance, these sensors receive acoustic signal from a sound source placed at far field distance (Plane Wave) and from broadside. I receive output of these sensors through individual preamplifiers, add them through hardware like summer circuit adder or in software after digitization and in this way got an...
I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
Thread 'Electromagnet magnetic field issue'
Hi Guys We are a bunch a mechanical engineers trying to build a simple electromagnet. Our design is based on a very similar magnet. However, our version is about 10 times less magnetic and we are wondering why. Our coil has exactly same length, same number of layers and turns. What is possibly wrong? PIN and bracket are made of iron and are in electrical contact, exactly like the reference design. Any help will be appreciated. Thanks. edit: even same wire diameter and coil was wounded by a...
Back
Top