r/Motors

We are looking for a motor with the following key specifications:

• 200 VAC, 400 Hz, 3-phase supply
• Rated speed: 23,000 RPM
• Approximate power: 1 kW
• Approximate current: 3.5 A/phase
• Operating temperature: −45°C to +55°C
• Compliance with MIL-STD-704D, MIL-STD-810G, and MIL-STD-461E
• Integrated thermal protection
• MIL-C-38999 Series III connector (or equivalent)

A lot of manufacturers told me such induction motor is not possible but the client already has one but that motor is not accessible to us. This motor is required for a Gearbox cooling fan in a Helicopter. Need guidance and if possible then quotes too.

EDIT: DM me if you require a detailed spec sheet.

I need to use an old woodworking jointer that belonged to my grandfather. It is currently unplugged. Where it sits, I have the option to plug it into either 120v or 240v. The motor tag is either long gone or I'm looking in the wrong place. The cord is still pliable enough that it isn't offering any clues. Since there is 240 there, I'm guessing it is 240, but what happens if I guess wrong? (In this case the only difference between the two receptacles is the 240v has a red plate and tag.) What is the safest way to approach this? I'm comfortable with residential electrical but haven't fooled with electric motors. Is there any way to identify the motor's wiring.

EDIT: I'm amused by the various down votes. It's an old building, it has issues. I have no idea who did the original electrical work, it wasn't my grandfather. The 240v outlets are clearly marked, even if technically incorrect. It's a work in progress. I've gotten as far as setting new main and sub panels, including a new sub panel for the shop. Unfortunately I can't get much further than that without moving a bunch of equipment and dismantling cabinetry. I've no space to do that at the moment because of other more pressing projects, like rebuilding damaged windows. I need the machines for those other projects. I'm the only person using the shop. This isn't a production space, it's a hobby shop. More importantly, were I to replace the receptacles, I would still be left with the question of how to identify the motor's current wiring, which is the root of the original question.

I have seen a number of hobbyist videos on youtube of people building BLDC motors using 3d printed parts. Of course I understand that most if not all of them are for educational purposes mainly, it got me intereseted in wanting to pursue a personal project of mine; To build an ebike BLDC motor.

I have however decided to go the 3d printing way as a form of learning myself before attempting what I set out to do. And I have done exactly that. I have built a 12slot 16pole stator core from 3d printed parts. I pretty much salvaged almost everything I needed from an old motor which included the bearings and insulated copper wire. I got some N35 magnets from aliexpress for my rotor.

Having done this project it got me thinking; how do motor manufactureres determine the rated voltage, power or even torque that their motors provide? I read somewhere that the winding turns, conductor size and even material selection play a role in determining these.

I understand that, for manufactureres they usually work backwards. As in they have a desired set of ratings in mind then using a combination of maths and design simulations work out all the parameters they need by leveraging Kv, Ke, Kt and Km constants.

My problem is, all the sources I have consulted (and by all sources I mean AI, since I could not find anything concrete) seem to be giving me entirely different approaches. Plus I don't trust AI that much in terms of this kind of information. I was hoping if someone could explain this to me or even direct me to some helpful resources.

I am looking for a relatively small, high performance brushless DC electric motor that can output in the range of 40-50 kw at 35,000 rpm for an electric pump I’m working on. Very similar to the ones used on the Rocketlab Rutherford engine. Is this even something I could buy?

This is the best one I could find, but the power would be slightly lower than I need at the required rpm, and I would rather not design a complex gearbox if I don’t have to

https://www.lehner-shop.com/en/inrunner/series-30/30100

Edit: I have a BS and MS in aerospace engineering, and have developed and successfully tested 2000 lbf liquid rocket engines. I know what I’m doing and am not in danger

I am working on and axial motor that has a magnetic axel meaning a magnet creates the center point of the rotation while a normal stator gives the force. While testing the stator i encountered wobble or an eliptical orbit that the rotor takes. these tests were done without the axial magnet on. is this normal for axial motors? Does the mechanical axel do all the wobble stopping usually? if so the magnetic one insnt too strong but i have shit tolerances of the stator and the magnetic poles of the rotor are not all concentric cause of complicated reasons. Should i bother fixing these or work on a stronger axel

Field-Oriented Control dominates modern motor drives, especially for PMSMs and BLDCs.

But CPUs are now absurdly powerful and inexpensive compared to when FOC became standard.

If motor control were reinvented from scratch today, would we still arrive at FOC, or are there alternative control strategies that were historically too computationally expensive to seriously consider?

Has motor control reached a local optimum, or are we just benefiting from decades of ecosystem momentum?

I'm using a VNH5200 motor driver for my RC Car. The datasheet provides a typical application circuit shown below. Underneath, it includes a note about a large blocking capacitor.

The circuit shows three symbols I don't understand. The one circled in red seems like it would be the large blocking capacitor, but why are there multiple connections to it? The capacitor circled in blue is a capacitor too, but that might just be a bypass capacitor. Can someone also confirm that the capacitor circled in blue should be connected to ground? Lastly, what is the component circled in green?

Edit: muC circled in red is the MCU

Edit 2: I'm confused by the purpose of the pull up resistors for the DIAG/EN pins -- are they not supposed to be controlled by the MCU? Are they connected to the MCU only for detecting a fault?

Also, 500uF is very large. Would an electrolytic capacitor suffice?

https://preview.redd.it/jpkhnj03wx8h1.png?width=1656&format=png&auto=webp&s=5cd7cec1c155326647bdfa22cba6e3b196e0ac98

Hey All,

I am working on a 6 axis robotic arm project right now and im using stepper motors. The stepper motors I am using are pretty beefy for obvious reasons. The motors are rated for 48V at 6 amps. The motor controller im using is supposed to be happy to accomplish this.

My power supply displays the amount of current being used however what I am reading is .45A. while my controller is set to request up to 5.9 amps. Where am I going wrong or is this expected behavior?

Thanks for the help!

Motor: (Not using the controller)

Driver: CNC Digital Stepper Driver DM556