Permeability in a DC Motor

Started by Anonymous in sci.electronics.basics6 years ago 15 replies

Two motors were evaluated to find the ratio of the speed of the rotor over the speed of the electron in the coil. ratio = speed(rotor) /...

Two motors were evaluated to find the ratio of the speed of the rotor over the speed of the electron in the coil. ratio = speed(rotor) / speed(electron) ratio = 8 meters per second / 10 microns per second Some calculations show that DC electric motors rotate thousands of times faster than the electrons move in the drive current. For example, the Mabuchi RE 280RA motor has a c


HOJO Motor

Started by sparky in sci.electronics.basics10 years ago 15 replies

Has anyone seen one of these actually work ? There are many people who say they work but no one has ever seen a working model without it...

Has anyone seen one of these actually work ? There are many people who say they work but no one has ever seen a working model without it being attached to some remote power source. Is it anything other than the scam it appears to be ?


why are stepper motors so hard to turn?

Started by Anonymous in sci.electronics.basics6 years ago 16 replies

I took apart an old inkjet printer and was surprised the stepper motor has such resistance to it, if it's just an iron gear rotor. What gives?

I took apart an old inkjet printer and was surprised the stepper motor has such resistance to it, if it's just an iron gear rotor. What gives?


Location of Passive RFID on Motor Vehicles

Started by Bret Cahill in sci.electronics.basics6 years ago 5 replies

Supposedly the active devices are often near the rear view mirror. Where are the passive RFIDs typically located when factory installed?

Supposedly the active devices are often near the rear view mirror. Where are the passive RFIDs typically located when factory installed?


Triac efficiency

Started by Anonymous in sci.electronics.basics4 years ago 10 replies

Hi everyone, When regulating the power to a motor or light, does the triac do so efficiently or does it dump the unwanted power as heat, as a...

Hi everyone, When regulating the power to a motor or light, does the triac do so efficiently or does it dump the unwanted power as heat, as a linear voltage regulator does? Thanks, Michael


Through Board Desoldering High Melting Point Solder

Started by Bret Cahill in sci.electronics.basics1 year ago 6 replies

The power wires for a 500 watt ebike motor go through the board. It there any off the shelf insulator designed to protect the caps and other...

The power wires for a 500 watt ebike motor go through the board. It there any off the shelf insulator designed to protect the caps and other components only 13 mm away? This is asking for a torch. Bret Cahill


DC motor soft start

Started by Bob Engelhardt in sci.electronics.basics2 months ago 6 replies

I found this neat soft-start circuit on the eevblog forum. Its neatness is that the gate threshold voltage occurs immediately and then the RC...

I found this neat soft-start circuit on the eevblog forum. Its neatness is that the gate threshold voltage occurs immediately and then the RC softness kicks in. V+ ________________________ V+ | | 1M ___________ V- |___1u___| | | | |-- |------| |-- | V- ____________| As...


How to slow down RPM of miter saw?

Started by John Doe in sci.electronics.basics7 years ago 48 replies

The motor runs on standard USA 120 V 60 Hz, 14 A, at 5500 RPM. What's the easiest way to slow down the RPM? What about simply adding a...

The motor runs on standard USA 120 V 60 Hz, 14 A, at 5500 RPM. What's the easiest way to slow down the RPM? What about simply adding a diode in series on the power cord? Any advice, references, and links would be appreciated. Thanks.


Dummy book on motors

Started by W. eWatson in sci.electronics.basics10 years ago 1 reply

I'm looking for some reasonably introductory book on motors, relays, gears, load, torque, and such. (See my Moving a Dome post on 11/14 as to...

I'm looking for some reasonably introductory book on motors, relays, gears, load, torque, and such. (See my Moving a Dome post on 11/14 as to what I'm attempting to do.) I do have a book by Hughes titled Electric Motors and Drives does a good job at motor fundamentals.


Rudimentary PC USB oscilloscope?

Started by John Doe in sci.electronics.basics6 years ago 20 replies

My main question is about PC USB-based oscilloscopes. The rest of this is specific to my problem(s) and may be overlooked. I'm using cordless...

My main question is about PC USB-based oscilloscopes. The rest of this is specific to my problem(s) and may be overlooked. I'm using cordless drills to power electric bicycles. I have one built. It works but is underpowered. I am building a better one using a DeWalt DCD995. Some nice electronics included in that drill, a stout (very tight turning) brushless motor with a controller. ...


Capacitor-run induction motor windings

Started by Anonymous in sci.electronics.basics4 years ago 5 replies

Hello, I'm hoping to convert old household induction motors to brushless motors basically by replacing the rotor with magnets. However I'm...

Hello, I'm hoping to convert old household induction motors to brushless motors basically by replacing the rotor with magnets. However I'm having difficulty understanding the stator winding patterns. I need to isolate the phases obviously. Any suggestions? Even if they are two phase instead of three phase, that is useful too. Thanks, Michael


Can someone translate this ? Russian to English

Started by gm in sci.electronics.basics4 years ago 11 replies

Hi to all. College of mine bought some Chinese motor controller but i can get any addition infos on Chinese site. Luckily i found that someone...

Hi to all. College of mine bought some Chinese motor controller but i can get any addition infos on Chinese site. Luckily i found that someone in Russia is using the same controller and he has wrote how to connect, but it in Russian language. Can someone please translate this ? https://ibb.co/i6zZ6w Thank you in advance !


MOSFET Question (Buzzer, Motor Drive, LED Driver) - Advice.

Started by Anonymous in sci.electronics.basics6 years ago 5 replies

Hello everyone I hope you are having a good day. I had three questions that correspond to the 3 sections of the schematic shown below. ...

Hello everyone I hope you are having a good day. I had three questions that correspond to the 3 sections of the schematic shown below. Question 1.) There is a piezoelectric buzzer that is shown below that gets connected to a microcontroller through resistors R9 and R10. Here is the part: http://www.digikey.com/product-s... Usually on a beeper I would just apply power


Circuit design needed

Started by Mark in sci.electronics.basics7 years ago 5 replies

I need to build an inexpensive circuit to open and close a 3volt DC power source at about 15 minute intervals. The circuit would need to open,...

I need to build an inexpensive circuit to open and close a 3volt DC power source at about 15 minute intervals. The circuit would need to open, then close again after a short delay say 500 milliseconds to a few seconds. I had thought about doing this mechanically with a slow rpm motor, gears and a micro switch, but there must be a circuit that can do this. Thanks


Servo motor recommendation sought

Started by D.M. Procida in sci.electronics.basics2 years ago 2 replies

For my plotter project I have experimented with a variety of different servo motors. Very cheap analog micro servos work very well (I have...

For my plotter project I have experimented with a variety of different servo motors. Very cheap analog micro servos work very well (I have been using Tower Pro SG90s), as you can see from the images on the site, but digital versions do not, because they are too twitchy. I'd like to try with some different digital (more expensive) servo motors to see if the


efficiencies of appliance 3-phase brushless motors?

Started by Anonymous in sci.electronics.basics3 years ago 26 replies

Hello, What is the ballpark efficiency range of washing machine or clothes dryer three-phase 110-volt AC motors? I'm debating tearing a...

Hello, What is the ballpark efficiency range of washing machine or clothes dryer three-phase 110-volt AC motors? I'm debating tearing a broken washing machine apart for the motor and controllers but was curious if the efficiency is too low to bother. Thanks, Michael


VFD for single phase induction motor?

Started by Anonymous in sci.electronics.basics3 years ago 2 replies

Is this possible? I have a customer, a glass artist, who uses several very nice but old glass grinding machines. There are only 4 speeds...

Is this possible? I have a customer, a glass artist, who uses several very nice but old glass grinding machines. There are only 4 speeds on these machines and he would really like more speeds. He has a newer machine with a VFD on it and asked me how he could get the same thing on his old machines. I told him he really needs to change motors to 3 phase. But he is loathe to do that. I can see w...


Major Differences In Small Engine Coils

Started by Bret Cahill in sci.electronics.basics10 years ago 7 replies

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer...

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer makes the coils for their 100 outboard, a 2 cylinder 4 stroke engine. Isn't it likely that other small engines, say from riding lawnmowers, use coils that are pretty much the same? For that matter couldn't a motor vehicle coil work? Bret Cahill ...


Power Routing Switch

Started by Rick C in sci.electronics.basics1 year ago 1 reply

Working on a gadget that uses a 12 volt motor (10 amp peak) and misc electr= onics running on lower voltages. It is powered from an external PSU...

Working on a gadget that uses a 12 volt motor (10 amp peak) and misc electr= onics running on lower voltages. It is powered from an external PSU like a= laptop supply, but 12 volts. There is also a sealed lead acid battery for= backup when the power fails. =20 This design uses pairs of pFETs to route the power from the 12 volts input = when present, or the battery when the line is not p...


Whole house fan motor

Started by telengard in sci.electronics.basics9 years ago 37 replies

Just recently purchased a house and it has a whole house fan. Unfortunately, the folks who installed the A/C disconnected the motorized louvers...

Just recently purchased a house and it has a whole house fan. Unfortunately, the folks who installed the A/C disconnected the motorized louvers to get into the crawl space a couple months ago and I'm not sure exactly how it was wired. In the crawl space there is a black (which had a wire nut on it) and bare wire and a white wire which looks like it was curled up to not use it (it is not stri...