Another benifit I remember for 3 phase power is that it creates a rotating magnetic field inside of motors by having 3 windings. This is good for starting a motor and setting its direction of rotation. Using single phase power, motors have to use some form of phase shifter to do the same thing. Also with 3 phase power, the total power is distributed over three wires instead of one or two, and therefore smaller wire is needed.
Bill and Jojo, I just happened to glance at the chat before logging out.
I was involved with aircraft work years ago. My instructors like to point out that 400Hz, 3 phase power was nearly DC when it came out of the rectifier. Smaller filter caps, redundant power supply if 1 phase fails were tsome of the benifits.
Bill: I'm not a power guy, but I would like to understand better the rational why 3-phase is more efficient than single phase. Is it because the load can be distributed better in 3-phase while single phase takes all the brunt?
MPEDRAZA--you may nbot need digital--but if you want to capture, retain, an dfurther analyze, you will. Question really is at what point in the signal chain to you go digital: at the front end, or further along the chain, after the analog calculation?
Davec3000: those ICs can be good options, yes. But you still have to think about what you are trying to measure. It's like using an "average": usually a good thing, but by definition, "average" obscures detaisl--and that may be very good, or very bad, for the situation.
Yes Bill, analog can be a simple solution. I tend to try compressing most operations into a uC with analog front-end to condition or pre-process. That would be the hybrid approach you mention. Hardware reuse is easier for me when a uC is used instead of a dedicated circuit.
Using Digital due to calculation and accuracy requirements -- better than 1% -- so using TI MSP43047197 SOC -- since it has 14 Bit ADC etc. Regulatory approval -- so not much choice for cumulative energy use. Complicated -- but that's the answer.
@bicyclebill: Second bullet on slide 3 suggests that 12 bits resolution (1 part in 4096) are required to digitize an analog value to 1% full scale. Is that what is meant? If it is, why not 7 bits (1 part in 128, which is approximately 1%)?
I'd like to see a poll: when checking failed fuses, is it acceptable to DVM across the fuse verses to earth/ground/common? I check to E/G/C, but the topic can bring heated discussions! (Temps here are expected to drop 25+ in 45 minutes or less!) :)
Your slides mention 12Bit accuracy for measurement. I am currently testing TI MSP430F57197 (SOC) for 3 Phase -- it has 7 X 16 Bit Ganged (simultaneous reading) ADC -- others in this lne have up to 24 bit ADC -- fwiw -- I have not checked other lines.
A middle school team from Rochester, Mich., has again nabbed the grand prize in the annual international Future City Competition, which drew students from 37 regions of the United States, as well as from England and China.
The word “smart” is becoming the dumbest word around. It has been applied to almost every device and system in our homes. In addition to smartphones and smart meters, we now hear about smart clothing and smart shoes, smart lights, smart homes, smart buildings, and every trendy city today has its smart city project. Just because it has a computer inside and is connected to the Web, does not mean it is smart.
Are you being paid enough? Do you want a better job? According to a recent survey Manpower released just before Engineers Week, employers and engineers don't see eye-to-eye about the state of US engineers' skills and experience.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.