How might electronics be different if AC voltage was 72V at 45 Hz?

[AlexB23]

Hey guys. I have a question related to electricity and alternating current. Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz. How would appliances be designed, and what impact would the lower frequency and voltage have on transformers, wiring, TVs, computers, LEDs, motors, and heating, assuming the laws of physics and technology are the same as on Earth?

 

[Baluncore]

Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz.

Instead of 115V 60Hz or 230V 50Hz ?

For the same power, currents would be higher, wires would need to be significantly heavier. Buy shares in the copper industry on Earth. Their home planet would need to have plenty of conductive metals on the surface.

Power poles would not be needed for voltage isolation, the heavy cables used for distribution would be buried underground in a suburb.

Insulation could be thinner, but not by much. Switches would be heavier since they carry more current, but have less voltage to sustain an arc when turning that current off. More switches would have mercury wetted contacts.

Transformers would be inefficient and heavy, with more core and windings. Motors would run slower.

 

[AlexB23]

Instead of 115V 60Hz or 230V 50Hz ?

For the same power, currents would be higher, wires would need to be significantly heavier. Buy shares in the copper industry on Earth. Their home planet would need to have plenty of conductive metals on the surface.

Power poles would not be needed for voltage isolation, the heavy cables used for distribution would be buried underground in a suburb.

Insulation could be thinner, but not by much. Switches would be heavier since they carry more current, but have less voltage to sustain an arc when turning that current off. More switches would have mercury wetted contacts.

Transformers would be inefficient and heavy, with more core and windings. Motors would run slower.

Yeah. So, could aluminum or steel wiring work? Of course, the high voltage lines would be in the dozens to hundreds of kV, so those can be in the sky, but then the home voltage can be 70-ish volts. So, how would a washing machine spin 1400 RPM? Would it need inverters?

 

[Borek]

Washing machines use transmission belts to get the required speed, so in this particular case the main difference would be just a different gear ratio.

Broadly speaking differences wouldn't be that large, I doubt they would be easy to spot for a layman.

 

[AlexB23]

Washing machines use transmission belts to get the required speed, so in this particular case the main difference would be just a different gear ratio.

Broadly speaking differences wouldn't be that large, I doubt they would be easy to spot for a layman.

Nice. Mine is direct drive, and inverter type.

 

[Baluncore]

Yeah. So, could aluminum or steel wiring work?

Because wiring heat losses are W = I²·R, aluminium wire would work, but never steel for the conductors, more likely copper or silver.

 

[Baluncore]

Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz.

If they were so silly as to standardise on such a low voltage and high current system, I doubt they would have advanced electrical technology very far. They would need to have a very different resource availability to justify that choice.
1 kW = 230V, 4.35A.
1 kW = 115V, 8.70A.
1 kW = 73V, 13.70A.

 

[AlexB23]

Because wiring heat losses are W = I²·R, aluminium wire would work, but never steel for the conductors, more likely copper or silver.

Nice. I am getting this now. Maybe for home usage, 73V works, while for business then maybe 146V.

 

[Averagesupernova]

Nice. Mine is direct drive, and inverter type.

I doubt a new one can be bought any different. Everyone thought when they came on the market that the reliability would be a problem but from what I've seen it's an improvement.

 

[AlexB23]

I doubt a new one can be bought any different. Everyone thought when they came on the market that the reliability would be a problem but from what I've seen it's an improvement.

Yeah, the inverter ones have good efficiency and no belt to deal with.

 

[Borek]

I doubt a new one can be bought any different.

Interesting. Could be something has changed lately or it is a difference between US/EU, but my previous one (bought ~10 years ago) was definitely with the transmission belt, not sure about the one we use now (and I won't risk opening it now to not void warranty, but next year - who knows).

 

[Averagesupernova]

Interesting. Could be something has changed lately or it is a difference between US/EU, but my previous one (bought ~10 years ago) was definitely with the transmission belt, not sure about the one we use now (and I won't risk opening it now to not void warranty, but next year - who knows).

There is definitely a different sound between the two. Once you realize it you'll always be able to tell the difference.

 

[Rob Trajon]

Hey guys. I have a question related to electricity and alternating current. Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz. How would appliances be designed, and what impact would the lower frequency and voltage have on transformers, wiring, TVs, computers, LEDs, motors, and heating, assuming the laws of physics and technology are the same as on Earth?

I'm not an engineer, but Australia uses (if I recall) 212V AC for everything. Makes things simpler? You mention a different "sound". Translating MW radar into sound we can hear (something as radar, we can't hear naturally), has allowed people to tell the type and mode of various radars almost immediately. Like two people saying the same words, you KNOW two different people are saying them. You might even think; "Hey, that's so-and-so, he sounds under the weather... Bonus: Electrical current can be used to "carry" communications. Often an overlooked hole, in communications hardening.

 

[AlexB23]

I'm not an engineer, but Australia uses (if I recall) 212V AC for everything. Makes things simpler? You mention a different "sound". Translating MW radar into sound we can hear (something as radar, we can't hear naturally), has allowed people to tell the type and mode of various radars almost immediately. Like two people saying the same words, you KNOW two different people are saying them. You might even think; "Hey, that's so-and-so, he sounds under the weather... Bonus: Electrical current can be used to "carry" communications. Often an overlooked hole, in communications hardening.

Well, electrical hum in the US is 60 Hz, so a 46 Hz would sound lower pitched. Australia uses 230V at 50 Hz.

 

[Baluncore]

Australia uses (if I recall) 212V AC for everything.

AlexB23 is correct, Australia now employs the international standard, 230V at 50Hz. There is a broad voltage tolerance, so in many places it still measures the same as the old 240V standard, while it fully complies with the preset 230V standard.

Translating MW radar into sound we can hear (something as radar, we can't hear naturally), has allowed people to tell the type and mode of various radars almost immediately.

If MW radar is microwave RADAR, then when detected, you can hear the PRF, (Pulse Repetition Frequency), of the microwave radiation with its harmonics, as it sweeps across you. The PRF will depend on the range being searched, as generally, the echo must get back before the next pulse. High PRF means the RADAR is looking nearby, while the lowest PRF means it is looking out as far as the horizon.

RADAR sets today are more statistical, so they add a dither time to each pulse transmitted, and so sound mushy. The display now shows a digital record of coincident reflections, which prevents synchronous interference from another RADAR, from appearing as artifacts on the screen.

But back to the transformer hum issue. For a 50Hz mains frequency, the magnetostriction of the metal in a transformer doubles that frequency, so a passer-by will hear a peculiar 100Hz pulse with harmonics. That sounds like a buzz, unlike the pure tone of a 50Hz sinewave.

 

[Rob Trajon]

AlexB23 is correct, Australia now employs the international standard, 230V at 50Hz. There is a broad voltage tolerance, so in many places it still measures the same as the old 240V standard, while it fully complies with the preset 230V standard.


If MW radar is microwave RADAR, then when detected, you can hear the PRF, (Pulse Repetition Frequency), of the microwave radiation with its harmonics, as it sweeps across you. The PRF will depend on the range being searched, as generally, the echo must get back before the next pulse. High PRF means the RADAR is looking nearby, while the lowest PRF means it is looking out as far as the horizon.

RADAR sets today are more statistical, so they add a dither time to each pulse transmitted, and so sound mushy. The display now shows a digital record of coincident reflections, which prevents synchronous interference from another RADAR, from appearing as artifacts on the screen.

But back to the transformer hum issue. For a 50Hz mains frequency, the magnetostriction of the metal in a transformer doubles that frequency, so a passer-by will hear a peculiar 100Hz pulse with harmonics. That sounds like a buzz, unlike the pure tone of a 50Hz sinewave.

Your correct. But even 30 years ago, military radar (not always civilian) could add a known "non-sensical artifact" to their emissions. To anyone trying to spoof it, it would look like non-sensical noise, which would be ignored by an enemy. It would be a signature, to "our guys" The original ID Friend or Foe, that pings back to the radar "interrogating" say any airplane only works if to any "nasty" airplane, thinks it's just noise. Historically, ground based radar could always pump more power to overwhelm early plans ECM. So we took a different track.

 

[Baluncore]

This thread is about low frequency, low voltage supply, not the game theory of ELINT and IFF etc.