Forum - Recent Threads

Driver Circuit for a Reciprocating Water Pump in a Medical Device

jw0752 — Wed, 03 Sep 2025 14:36:22 GMT

Hello Friends,

I am working on servicing a circuit board that is used in a Medical Dental sterilizer. The circuit boards used in this model of sterilizer seem to have a chronic problem with a circuit that drives a reciprocating water pump. Here is a schematic of the circuit that fails:

My question is what is the advantage to using this circuit configuaration to drive the pump? The gate of the N CH MOSFET turns on and pulls one leg of the load to the negative rail and also turns on the P CH MOSFET about 20 microseconds later pulling the other leg of the load up to the positive rail. While this seems to work quite well it seems to me to be an added complication to be switching both legs of the load. I am hoping for some insight into what the advantage might be in using this configuaration. The Rds (on) of the N CH is about 60 milli Ohm and the Rds of the P CH is about 13 milli Ohm. While I am not certain this is probably a Pulsed circuit as I suspect that the pump needs a Pulsed drive to properly function. My hope is that in better understanding the advantages of this circuit design I might be able to modify it to lower the present failure rate. Failure is usually a shorted P CH Mosfet, A Heat Destroyed N CH MOSFET and a Shorted D26 Diode.

Any insights you may have will be appreciated.

John

Universal motors

MartinBonner — Thu, 06 Mar 2025 13:13:57 GMT

As Universal Motors can be powered by AC and DC power I understand that if there’s a different ratio of power (positive) going to one side of the armature , there’s a difference between torque and speed . More positive power to the armiture than the field , it results in more torque at the expense of speed , more speed , less torque if reversed .

how can I automate the torque/speed ratio if/when the motor is under load (or not)

I tried asking on another forum and they were less than helpful

Why did the micro servo zero position move?

colporteur — Mon, 03 Jul 2023 03:00:47 GMT

I‘ve started to use more Micro Servo Motor SG90S 9G servos controlled by a Nano using the Servo.h library provided in the Arduino IDE. The servo's are inexpensive (cheap) for the small animation projects they are used in.

I noticed an anomaly that is troubling. The servo’s zero position when first install has moved.

My knowledge of servo operation tells me that the position of the arm is based on the millisecond pulse provided from the controller. The servo rotates to the position indicated by the pulse.

I installed a servo and zero’d it before positioning the arm to move a shaft up and down. The servo worked for a few weeks. Today the physical position of the arm for zero has moved 90 degrees compared to when it was installed. Nothing has changed! The code is the same and the Nano used is the same.

I'm using a servo because of zero position. The code zero's the servo before starting. Then the codes moves the arm to the desired position. If zero moves, that is not good.

I’m hoping someone might have some insight into why zero has changed. Maybe there is something I can do to prevent this from happening. Same Nano, same code, just todays reboot put the servo zero arm in a different place for zero.

What is a reasonable expectation for a servo?

Components needed for pan tilt stepper motor(s)

amrrahmy — Wed, 25 May 2022 14:49:42 GMT

Background:

i am a software engineer, and have made a few iot pcb prototypes and integrated a lot of sensors and embedded devices.

Not familiar with stepper motors.

current project:

I wanted to buy/make motorized 3d scanner/camera that can work as a 3d room scanner. I was thinking having a camera on a tripod is better than hand holding the camera in terms of motion blur/focus ..etc. This is to create multiple image+depth information from different locations around the room to create a point cloud or 3d model, that requires some but limited manual tweaking to finally produce a decent and somewhat detailed 3d model of a room.

from the available and somewhat affordable options I saw were 3d cameras with depth information, as i saw decent results from app on iphone 12 plus depth or tof sensor, so i think i should be able to make a program that does similar or more accurate 3d scanning.

I am going to get this to test,

orbbec Astra+ or Astra plus. similar to intel realsense but it seems people are suggesting that intel is abandoning realsense and I saw multiple products EOL-ed.

https://orbbec3d.com/index/Product/info.html?cate=38&id=9

Dimensions	178.3235.3238.10mm
Weight	252g

I was thinking of placing that camera on a motorized pan tilt sensor,

something like,

https://www.amazon.ae/Motorized-Control-Rotation-Adapter-Cameras/dp/B08R6TGD65/ref=sr_1_1?crid=3M6M5UYC77U7H&keywords=pan+tilt+tripod&qid=1653487920&sprefix=pan+tilt+tripod%2Caps%2C175&sr=8-1

https://www.amazon.com/YT-260-Remote-Control-Motorized-Extreme/dp/B07NKVZCQZ

which seems fine, but I wanted to control the pan tilt myself, so i can program the movement, and time when the photos are taken in an automated way, so i was thinking maybe I can get a stepper motor or two like,

- NEMA-17 https://www.adafruit.com/product/324

- some hardware and brackets?

- some motor driver or shield for Arduino or raspberry pi?

- some adapters to go from a tripod mount to pan tilt device to the camera?

but i am not familiar with motors and the components needed to make a decent pan tilt kit/device. Advise is appreciated.

Maybe something like this,

Mini Pan-Tilt Kit - Assembled with Micro Servos

https://www.adafruit.com/product/1967

but preferably in metal or aluminum and maybe the rotation to be on axis if possible instead of off axis or above axis, unless something like the link is enough if i change the motors with stepper motors. i have used these hobby servos in the past and I know that they don't really move in accurate "steps", which is not a strict requirement for me, but i think more accurate movement might lead to less corrections and processing in my application.

alternative options to have motorized 3d scanning solutions or components are welcome.

How can i calculate pulse lenght for microcontroller driven srm motor?

madthescientist — Tue, 03 Aug 2021 22:54:19 GMT

I would like to drive a switched reluctance motor using a microcontroller.

Having 3 coils and a "+" shaped rotor, i would like to ask how can i calculate on and off time for speeds like 900rpm, 1200rpm, 1800 rpm, etc etc, so i can include the proper values in

the code for the microcontroller. I plan to use this set up on several experiments, that's the reason i need to code proper speeds.

What Would You Do with the K4 Drive System Development Kit?

rscasny — Tue, 21 Jul 2020 20:56:22 GMT

Ever so often I get a chance to offer to the element14 community a real jewel of a development kit. I think the K4 Drive System Development Kit by ebm-papst is one of those kinds of kits. Let me tell you a few things about it.

Let me start with a picture:

Here's what's in the kit:

• K4 Switch Box

• ECI-63.40 or VDC-3-49.15 Motor (-002 and -003 kit versions only)

• RS485 adapter

• RS485 adapter driver download CD

• USB-A to USB-B cable

• RS485 connection wires

What can you do with it:

In a nutshell, BLDC motor drive development. You get a motor with gearbox and a switchbox for some serious exploration of this drive system kit.!

Here's a few facts about the K4 Switch box:

The motor supply terminals are the power input to the motor and the DC to DC converter in the box that generates

24V logic power for the motor’s electronics. Red is positive, black is negative (ground).

• The motor and logic fuses protect the motor from an over current in the event too much power is drawn.

• The motor connector port provides the electrical contact between the Switch Box outputs and the motor inputs.

• The RS485 terminals are the inputs for communication between the motor and a computer via the USB to RS485

adapter included in the kit.

• The readout terminals are meant to allow for monitoring different voltages and provide feedback from the motor.

• The input switches control the digital 24V signals to the motor, which enable and control motor operation. The

switches have 3 positions: Up is toggle-on, middle is off, down is momentary-on.

• The 0-10V analog dial controls the analog voltage signal generated by the Switch Box and read by the motor. This

is usually used as a speed control signal.

What would you build with it:

On the serious side, any kind of high performance, position, torque or motor drive application. But, this is element14, let's get creative! Take a look at this cute video and see what one clever engineer did to automate the pouring of his cup of tea. Of course, he used the K4 Drive System Development Kit

www.youtube.com/watch

Are you interesting in obtaining this kit?

Reply to this discussion and tell me what you would do with it

P.S. here's the user manual to read and review.

Would you be interested in roadtesting Digital Motor Controller for Brushed DC Motors and used in FIRST Robotics Competitions?

rscasny — Thu, 26 Sep 2019 18:29:06 GMT

Like many of you know, I manage the element14 RoadTest program. In this role, I work with suppliers to select products to roadtest. I was offered this product, a Diglient Digitial Motor Controller dev board recently. I'm writing today to gauge how interested the community would be in roadtesting this product. Let me briefly tell you about it.

The DMC60C is a compact motor driver designed for 12V brushed DC motors. It's a drop-in replacement for Digilent's first generation PWM-only DMC60 and it supports for CAN communication. The DMC60C comes with a free configuration utility and demonstration code to help users get up and running quickly.

Another interesting piece of information is that this product is an approved motor controller for FIRST Robotics Competitions (FRC), which are meant to inspire young people to be science and technology leaders and innovators, by engaging them in exciting mentor-based programs that build science, engineering, and technology skills, that inspire innovation, and that foster well-rounded life capabilities including self-confidence, communication, and leadership. Sounds pretty good, right?

Here's some specs:

Sealed, ruggedized, and compact aluminum case designed to protect and prevent debris from entering the controller.
Large gauge input/output cables with flexible silicone insulation that are robustly attached to prevent vibration "shake off".
Tie-wrap and through-bolt mounting designed so the controller can be mounted directly onto the robot frame.
Reversible motor controller that can run motors in forward and backwards direction.
Can run both open loop control or closed loop control.
Designed to connect directly to a brushed 12V DC Motor, but can be used with other motors that are in the 12-24V range.
Four multi-color LEDs to indicate speed, direction, status, and error codes for easier debugging.
Brake/Coast Calibration button enables one-touch setting changes and simple calibration.

You can go here for some More InformationMore Information

What do you think? Would you be interesting in roadtesting this product? Please leave a comment if you have the time. Thanks.

How are you using AC/DC Motors Drives in your IIoT Design

rscasny — Sun, 01 Sep 2019 16:07:55 GMT

Motor Drives are more than a standalone speed/torque controller for your plant floor process machinery. They are an integral component of an automation system. There benefits on the factory floor generally include better energy efficiency, improved safety, better repeatability, and decreased downtime, etc. In the world of IIOT, they are a connected device such that they can gather data to be used for overall process improvements.

In what in and interesting ways are you utilizing AC/DC drives in your IIoT design?

Heater Pack

Workshopshed — Wed, 26 Sep 2018 08:48:24 GMT

Here's a close up picture of the "Heater Pack" mentioned in my status message. shabaz

three-phase "Yes, they are motor thermal overload elements, known as 'heaters' in old school speak. The elements would screw into a holder that would house the auxiliary contact and operating mechanism. So you could select the best size heater element to match the motor and install them into the holder.

Instead of holding multiple thermal overloads as we do now, we would just have the holder and then a range of different heater elements to select from.

Some work on bending a metal strip to operate the contacts, similar to modern thermal overload elements and some are melting alloy types that have a star wheel held solid in a solder pot and the heat through the element would melt the soda and allow the star wheel to rotate and flip the mechanism to break the contacts. The ones you have look more like the former.

I will have a look at work tomorrow and see if I have a complete assembly and take some pictures if so.

Great idea for the maker box though!"

AC TO DC Motor

sneb — Mon, 27 Aug 2018 15:07:46 GMT

Hello All,

Is there away of converting an AC Induction Motor to run off a DC source without an inverter? (DIY) if possible....

Any Advice will be much appreciated.....

Tower Pro SG90 microservo question.

sanyika95 — Wed, 04 Jul 2018 22:18:21 GMT

Hello!

I have a question regarding this kind of motors. I am using my Raspberry Pi with the RPi.GPIO library. I have 4 of this motor, I have tested 2 and both of them worked as I write below.

On thier datasheet it is written that I can control them with a signal which frequency is 50Hz and the voltage is around 5V.

Also on the datasheet the -90° rotation needs 1 ms pulse, which would mean that, the duty cycle should be 5%. This works perfectly.

On the datasheet the +90° rotation needs 2 ms pulse, which would mean that, the duty cycle should be 10%. This doesnt works. The +90° rotation is at around 20% duty cycle.

This is the datasheet I found: http://www.ee.ic.ac.uk/pcheung/teaching/DE1_EE/stores/sg90_datasheet.pdf

Are the motors wrong, or did I understand something badly, or the PWM on the Raspberry Pi is this bad with that library? (I have read something back then it is not the perfect library for motor control)

Crydom D1D100 SSR

have2sail75 — Mon, 26 Mar 2018 21:09:29 GMT

Powering my small sailboat with electric motor Have most of my parts installed BLDC/PMAC motor came set up with this SSR Kelly controller all wired Can I connect my BMS LVC cutoff to Crydom D1D100D1D100 SSR to cut off all power to motor

Attachments:


community.element14.com/.../Parts-list-for-wiring.docx	Parts list for wiring.docx

3V Motor Control using Arduino

ross2609 — Sat, 10 Feb 2018 14:13:37 GMT

I'm not too familiar with Arduino's but I'm very interested to get involved with them as I would like to build my own projects!

The circuit that I have built is shown below:

I am trying to control 3V DC motor using the PWM pins on the Arduino. I'm using an LDR in a voltage divider to provide an analog input into the A0 pin. The code I'm using is provided below:

int sensorPin = A0; // select the input pin for the voltage read from sensor

int motorPin = 9; // select the pin for the motor

int sensorValue = 0; // variable to store the value coming from the sensor

int val = 0;

void setup() {

//set the pin mode for the motor to be an output

pinMode(motorPin, OUTPUT);

Serial.begin(9600);

}

void loop() {

// read the value from the sensor:

sensorValue = analogRead(sensorPin);

//Print the value read on A0 into the serial monitor.

Serial.print(sensorValue);

Serial.print(' ');

delay(1000);

//sensorPin ranges between 0 -> 1023 so val ranges between 0 -> 255.

val = sensorPin/4;

//Motor speed changes relative to the value read at A0.

analogWrite(motorPin, val);

}

THE PROBLEM:

I can't see what is wrong with the circuit but the output voltage from the PWM pin 9 always seems to be roughly 0.05V and the VCC voltage 3.3V is all being dropped across VCE. Therefore I have concluded that there is no current flowing through the transistor.

I am not sure how to solve this problem.

Thanks for any help!

Driving high-side N-Chanel mosfet

nicoloquinte — Thu, 04 Jan 2018 00:29:12 GMT

Some time ago Istarted a quadcopter project but the ESCs appeared to be expensive, so Idecided tu build my ones with components and I'm like facing a problem with mosfets (since I don't wanted to une P-chanel ones) and I Have some questions :

1): I have these buck drivers but I've burnt 2 of them by trying to use them as normal drivers.

I cant buy another ones.

if I could,how ?

2)if not : I have already saw an esc with only n-chanels mosfets with no drivers on it but only components near them ; can I build a bootstrap circuit on my own ?

thx.

nico

Interested in Evaluating 3-Phase Motor Drive Application Kit?

rscasny — Thu, 05 Oct 2017 22:01:58 GMT

Are you interested in Motor control?

Do you have experience designing Motor Drive Boards for 115/230 V motor drive applications?

Then read the following and click the link to learn more.

he iMOTION™ MADK evaluation platform covers 115/230 V motor drive applications up to 300 W. The platform is offering a modular and scalable system solution with 2 different control board options and a range of power boards. One control board option is a stan dard ARM® Cortex®-M0 Microcontroller XMC1302 with tailored motor control peripherals and MATH hardware accelerator. Another option is an iMOTION™ IRMCK099 digital motion control IC with integrated Motor Control Engine (MCE).

EVALM113020565DTOBO1 (3 Kits)

The EVALM113020565DTOBO1EVALM113020565DTOBO1 from Infineon is an evaluation kit which provides compact and flexible 3-phase motor drive system solution platform with control card and power stage powered by IRSM505-065DA2IRSM505-065DA2 IPM DIP and XMC 1302 IRSM505-065 is a 3-phase integrated power module(IPM designed for advanced appliance motor drive applications such as energy efficient fans and pumps The XMC1302 microcontroller brings together the ARM Cortex-M0 core and market proven and differentiating peripherals in a leading edge 65nm manufacturing process To get a functioning motor system running in less than 1 hour all needed is included Such as control card with debug interface and complete power stage Motor control software is preloaded or available for download Easy to use GUI software for parameterisation and tuning is available as well

EVALM1099MTOBO1 (4 Kits)

The EVALM1099MTOBO1EVALM1099MTOBO1 from Infineon is an iMOTION motor control board for MADK based on IRMCK099 device The IRMCK099 is an iMOTION motor control IC for single motor drive It combines the iMOTION motor control engine(MCE with all peripherals required to realize a complete variable speed drive The board offers a MCE designer GUI for parameterization and tuning

Click Here If You Are Interested in Evaluating A Motor Drive Dev Kit? You'll Get A Chance to Receive the Kit For Free!

IGBT Motor Controller

rsc — Mon, 28 Aug 2017 19:28:09 GMT

I built a go-kart a few years back and used a CM600 IGBT for the controller. It died on me one day without any warning, and I'm thinking about rebuilding the controller.

I'm looking for some input on IGBT drive circuits. I was just PWM'in the gate, and I think it just lached up on me. I was told that my driver needed dead time and a strong pull down for

solid turn off. I'm looking for my old driver schematics, but I fear they are lost in some old discarded hard drive. The motor was an aircraft 14VDC starter motor approx. 1HP.

I was driving it with 2 marine deep cycle batteries in series. I had a calibrated shunt in series with the GND, and it was drawing 350A at full load.

I'm probably going to start from scratch with the new controller, any input from anyone with this size motor controller experience would be appreciated.

Here's a pic of the kart before I added the controller:

Here's a link to a video when the kart was just built running at 12V

https://www.youtube.com/watch?v=6mpljZAdMWE&t=13s

choosing a motor and parts.

gio_dude — Mon, 28 Aug 2017 17:37:27 GMT

Sorry about the simple questions in advance but I'm very new to motors.

So I wanted to make a retractable window curtain the goes up and down and coils on to its self. So what I was thinking was bluetooth or wifi feather from adafruit with their motor driver wing (https://www.adafruit.com/product/2927 ). A motor on a rod with the curtain hanging from it.

So if I'm missing something that will make this project completely fail in my face please tell me.

here are my questions

what type of motor should choose?

I've been reading a lot about stepper motor and they look promising since I can have more precision.

What type of torque do i need to be looking at.

I read the post about torque and need to read it a few more times to understand it all but it doesn't sound like I need a lot of torque.

Motor to rod connection.

I don't know terms very well and looking at 3d printers they use a coupler to attach the motor to a rod. is there a different way i should research or a better way of doing it.

Dual motor

I was thinking about using a motor on each side one wired in reverse is that a good idea.

thanks in advance

DC motor as generator

vinceverc — Sat, 12 Aug 2017 14:58:13 GMT

Hello everyone,
This question might have been asked somewhere else but I was not able to fand any other posts regarding my question, if there are please link them and i will delete this post, so I don't waste anybody's time.

I was recently looking into making a generator. I found some glow engines that don't cost alot (I am on a budget) like this one from ali express (I can also buy from other websites, this one just showed up first): https://www.aliexpress.com/item/GO-Engine-18th-methanol-engine-3-0CC-Without-Glow-Plug-for-1-10-on-road-Buggy/32804111807.html?spm=2114.search0204.3.287.c3ltkE&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_10068_5430020_5410020_10304_10307_10137_10060_10302_10155_10154_5370011_10056_10055_10054_10059_100031_10099_5400020_10103_10102_10052_10053_10142_10107_10050_10051_5380020_5390020_10084_10083_10080_10082_10081_10177_10110_10111_5420020_10112_10113_10114_10312_10313_10314_10315_10078_10079_10073,searchweb201603_16,ppcSwitch_5_ppcChannel&btsid=982ac520-824a-4967-816b-8c0d979ee8e4&algo_expid=9ff6c1ab-f534-4c27-94b5-31bdddab7c71-39&algo_pvid=9ff6c1ab-f534-4c27-94b5-31bdddab7c71

And I was looking around for a dc motor But I don't know which one to pick. Should i be brushed or brushless? What rpm? what voltage? what amp rating? I heard some motors generate AC and others dc?

I am looking to power something like a buck boost converter to charge 5v things (like phones or camping lights... etc).
Will it provide enough power for these appliances?

Thanks in advance.

Vince

Synching Motors

electronics625 — Sun, 12 Mar 2017 18:02:56 GMT

I am new to electronics so I do not know too much. My question concerns synching two Minn kota trolling motors to run at the same thrust. I want to mount two trolling motors on the front of my boat. Both of these motors have a low thrust so I would like to use two but sync them so they do not cause the boat to pull to one side oor the other. I have been reading books and articles to see if this is possible but have not been able to determine if this can be done through a circuit board and if so what approach to use.

RC Car with Pocket Bike engine!

tchico_grk — Mon, 06 Feb 2017 23:59:04 GMT

Hi everyone! I have a question on the title...
I already have a fully working pocket bike, and one day I was seeing old stuff and saw an battery Rc car and started to think why not fuse them together?

Besides building the chassis, that would be a "design" of mine and all that stuff, what would I need from the electronic part for the car fully operates the engine? Is there any type of tutorial to HOW TO? If so, thank you!

Selecting the Bldc evaluation board

dineshch — Mon, 14 Nov 2016 12:00:44 GMT

Hii I'm using 48V 20A maximum rating brushless DC motor. I want an evaluation board which can work that BLDC motor. Can anyone suggest a low cost board. I have found only DRV8301-69M-kit but it's too costly. I'm looking for another board which is cheaper than that.

Unidentifiable Motor

me-al — Sat, 29 Oct 2016 00:41:51 GMT

Hello,

I'm trying to determine what kind of DC motor I have here; I can't find it on the internet. I would like its spec's and where I can find more. It is from a BMW E90 and provides the mechanical power for the steering lock. Instead of strips or wires, it has a female plug for current.

Attachments:

community.element14.com/.../Johnson-Motor.pdf

Johnson Motor.pdf

large 1/2 HP induction motor

Former Member — Fri, 04 Mar 2016 22:48:39 GMT

Can anyone make sense of this schematic for me? it is for a old 1/2 HP induction motor from a washing

machine and the most i have been able to do is get the motor to spin slowly with help to get it spinning

Motor driver

rishi2628 — Tue, 30 Jun 2015 05:59:06 GMT

Can anybody suggest me a motor driver ic or module that could provide 24 Volts 20 Amps of current??

Torque

rishi2628 — Tue, 23 Jun 2015 01:48:17 GMT

I have am dc geared motor like the one below. On the box it is written that it is a 12kgcm torque motor. What does it mean? Does it mean that the motor can carry 12 kg weight with a speed of 1 cm per second? FYI, I am participating in a robowars competition and i need motors to drive a 60 kg robot.This is my first time and i have no clue how to make a battling bot. So i hope you can give me any suggestion or advice, if possible.Thanks

Attachments: