Dear All,
I would be grateful if you can help me. Our steel company want to buy a furnace with 25 ton capacity for continuous casting process. We are confused with type of furnace we should select (Induction or arc electrical furnace). I read alot of information on internet and I am still...
Dear All,
I have a question and I would be grateful if you can help me to find its answer. I saw in some hydraulic circuits they use 2 accumulators for both high and lower pressure. I don't understand why they use two. I would be grateful if you help
Dear All,
I am confused in the calculation the frequency response (amplitude ratio and phase shift). What is the frequency units? Is it rad/sec or hertz?
Dear all,
I have a question regarding using PI or PD control based on the control variable. Is there a relation? As I found a lot of people use PI controller for speed or current control for servo systems. However, PD is used a lot for position or force control. I am wondering if there are...
Dear All,
I am wondering if it okay to have cascaded torque and current control loops to control the torque of a system driven by DC motor. The torque control will be the outer loop and has the set torque value and the current is the inner control loop on the DC motor. Is that okay? or it is...
Dear All,
I am looking to do PID torque control on a mechanical system derived by DC motor. The system has torque sensor to measure the actual torque on the system and the motor is derived by PWM motor driver. The PWM motor driver can work in either voltage control or current control. The input...
Dear All,
I have a question related to using power screw. Power screw is used to convert torque into axial forces on the nut. The axial forces between the nut and power screw will be equal and opposite to each other and the applied torque on the screw is function in applied forces. My question...
Hi
I have a question related to PWM vs. Linear Amplifier. I know the PWM amplifiers run cooler than standard linear power amplifiers and hence the PWM amplifiers has higher efficiency. I am wondering what about the motor itself. Are both PWM vs. Linear Amplifier produces the same heat losses on...
Hello
I am using a DC motor which is drived by H-bridge. The input to the motor coil is 53.1khz PWM signal. Is the effective voltage on the motor coil: the average voltage or the true rms voltage. Is normal digital multimeter can measure the effective voltage on the motor coil correctly?
Thanks...
Dear All,
I want to measure the actual power consumption by brushless DC motor. In case of brush DC motor I used voltage divider and current sensor to measure the voltage and current accross the brush DC motor coil and then calculate the electrical power. However in case of brushless DC motor, I...
Dear All,
My background is mechanical and I was looking to understand the theory of regenerative braking in DC motors. I found this article online http://www.pmdcorp.com/news/articles/html/Regenerative_Braking_Deep_Dive.html
In Figure 3, it shows that in braking quadrants 2 and 4 there is...
Dear All,
I would like to measure bending moment on tube without measuring all other forces and moments. I am planning to use four strain gauges to measure the bending using full bridges. I am little confused between using tee rosette strain gauges similar to this one...
I designed a force sensor using strain gauges to measure the force components in two directions. The forces creates compression and tension in x-direction while creates compression only in z-direction. I am looking for a commercial load cell amplifiers which has low pass filter (about 20Hz) and...
Dear All,
I am looking for a small lightweight electromagnetic clutch which is engaged and transmit power by default and when I activate it, it will disengage and overrun a timing pulley. The maximum transmitted torque is about 0.6Nm and maximum speed is about 3000rpm. Do you have an idea which...
Hi there,
I was using a ball screw a test rig four years ago, then we store it for one year and half. When we tried to use it again, we realized that it has more friction and heavy movement compare to before. Do you have an idea how to get it back to the same performance and reduce the friction...
