# Recent content by marellasunny

1. ### Automotive Calculating the angular acceleration of a swivel seat

Angular acceleration of 0.034 rad/sec2 sounds about right for this application. I make the mistake of not considering the right acceleration time- just the 7.5 seconds, in fact the motors would accelerate, steady and decelerate in a trapezoidal fashion. This was very helpful.
2. ### Automotive Calculating the angular acceleration of a swivel seat

We have an automotive swivel seat that turns from the initial seating position to the final position outside the vehicle (90 degree swivel in 15 seconds). We would like to calculate the torque required for rotating the seat along with the person. We have calculated the inertia of the movable...
3. ### 500 kg Solar CSP reflector dish mechanism problem

Thanks for the reply Nidum. Detecting if the drive is behaving abnormally would be possible only if I use a current sensor to sense actuator-block. By actuator-block I mean that some part of the mechanism in the system has malfunctioned/stuck. In this case, the motor driver would see a sudden...
4. ### 500 kg Solar CSP reflector dish mechanism problem

Hi JBA. I hope the photo above makes it clear to you where the swivel point of the dish exactly is. This is an eccentric rotation. I've marked in the photo where I would place the actuator and top-support assembly. The top-support assembly would be a prismatic mechanism with a rod moving inside...
5. ### 500 kg Solar CSP reflector dish mechanism problem

Hi Oz. We did not manufacture these dishes, so I'm not too sure on the material although I could take a guess. These are not SS, probably silver and copper coating on glass. Price of PV unfortunately does not have major effect on CSP. These are just reflectors and have no photovoltaic...
6. ### 500 kg Solar CSP reflector dish mechanism problem

I am currently re-fabricating solar concentrator dishes to allow for automatic tracking of the sun during the day and month. The industry term for these dishes is 'CSP' (Concentrated Solar Power). Task at hand: The CSP parabolic dishes are currently manually adjusted to the position of the sun...
7. ### Reliability of low-cost accelerometers in commercial applications

Thank you for the reply. No this is not a critical application like aircraft systems. Although, if accelerometer did fail in my system, errors would accumulate over a period of few days and system positioning would become highly inaccurate. No safety issue though. The reason 2 cheap...
8. ### Reliability of low-cost accelerometers in commercial applications

My question relates to the reliability of low-cost accelerometers (MMA7455,ADXL345 etc.) in commercial products with a expected life expectancy of 5 years or more. The tilt angle reading from the accelerometer will be used as a feedback parameter to orient a single-axis plate-reflector...
9. ### Linear actuator limit switch replacement/repair

S2M implies surface mount? Then I'm thinking of using the 1N5408 as per the spec sheets. Yeah I see the smd diodes on top, numbers blackened out . Thanks for the tip. https://en.wikipedia.org/wiki/1N400x_general-purpose_diodes
10. ### Linear actuator limit switch replacement/repair

Apologies for the late reply. The motor no longer works. Hopefully its because some passive component got burnt-up. 1 good thing that seems to have emerged is that I have come closer to understanding the inner workings of the linear actuator. Please find attached the pics with descriptions of...
11. ### Alternatives to varistors as overload protection at DC motor

Thanks for the replies. FYI I managed to only get hold of 130V clamping voltage varistors. Nothing in the range of 18V is available. So, I'm thinking of connecting series-opposing 15V zener diodes instead. Is that okay? CWatters- "If you are concerned about something stalling/blocking the...
12. ### Alternatives to varistors as overload protection at DC motor

Alternatives to varistors as overload protection at DC motor DC Motor here implies 12V linear actuator w/DC Motor that consumes 2.8A under loading condition. Pretty costly equipment. I'm using a L298N motor driver connected in parallel to run the linear actuator. The motor driver is run by a...
13. ### Linear actuator limit switch replacement/repair

Linear actuator spec.: 400mm stroke, 6000N, 2 limit switches, 5mm/sec, 12V DC supply, BIBUS IP65 casing. One of the limit switches of my LA (Linear Actuator) seems to have burned out. This happened because I accidentally plugged the LA leads into the AC mains socket (my LA is rated to run at...
14. ### Automotive X shaped roof profile for small series car-production method

Hi all! I need to decide on the production philosophy of an SEV(small electric vehicle) as a final part of my thesis project. Up until now, I have designed the package layout and body and performed a FE analysis (topology optimization) to arrive at a reasonable body-in-white structure. I did a...
15. ### Front crash with crumple zone: relative velocity calculation

EURONCAP front crash test involves crashing a car moving at 64 kph onto a deformable barrier at 40% of the total vehicle width. According to the EURONCAP website, this is equivalent to two vehicles crashing into each other at 55 kph. How did they arrive at this figure? I presumed that the...