Electric motors

Whilst searching for a suitable brushless DC motor for a friend in the States to fit to his BCA jig borer I came across eBay Item number 225 466 391 205.

This is a motor and servo controller sold as a plug and play system without the hardware associated with the Sewing machine offerings. The motors and matching controllers come in several power rating from 550W to 2.2kw so should suit someone wish to use this technology.

CS

Yet again cheap chinese junk that does not meet UK or EU safety standards. I can tell that just from the images. The connectors on the motor are not safe for use at the voltages that the motor runs on. Tha input voltage is not compatible with UK mains. The markings are not in english.

Buer beware, this could kill you or someone else.

Robert.

Clive,

Doing the due diligence thing and checking the feedback none of those units have ever been sold by that seller.

All the similar sellers have similar low feedback and sell the same gun related gear, but no electric motors so far. it's likely you would end up waiting a long time for them to ship.

Picking up on what Robert is saying the connectors appear to be quite lightweight for what would be UK 4A or US 8A if fed straight off the mains so the controller must be pushing significant DC voltage.

I hadn't made an in-depth investigation into the product before suggesting it may be suitable for driving a machine and I had taken the advert on face value. Robert may have a point about the connectors but a lot of electrical/electronic connectors, although meeting EU/UK Domestic use standards, may not suitable for their final operating environment. I think the connectors Robert has doubts about are the two used to connect the motor to the controller. One will be the Hall signals @ 5V & < 10mA but the other is for the motor phase windings using 3 - 4 Amps @ 300+ volts. The pictures shows a motor similar to the one I have on my Pultra lathe which from personal internal inspection is of good quality and design. Maybe someone in China is noticing how the sewing machine motors are finding alternative application and reacting to the market opportunity.

I can't agree that cheap Chinese = Junk as I remember that Japanese products once had the same reputation. I also remember the design and build "quality" that some British products had.

There are many devices, and not just electrical ones, that are being bought that do not comply with a whole plethora of modern safety standards and these include old high quality British induction motors. These may be a problem if the user/purchaser doesn't understand the possible issues or seek advice and in part that is what this forum is about.

As they say the handbook, if there is one , is for the guidance of wise men and the obedience of fools and if there are still any doubts ASK.

CS

I was not implying that all chinese items are junk, but this is

The metal bodied connectors used for the motor power and feedback are not safe for use on the voltages that the motor runs on.

Trouble is people ignore the rules due to "normalisation" of the supply and use of non-compliant items - until someone dies then the fertiliser hits the air mover. Then there is a clamp down or / and knee-jerk legislation that also affects the people who were doing the right thing as well as the chancers.
An example of this is the proposal to make e-bike compliance subject to 3rd party review. This will add cost and delay to market for responsibe manufacturers whose bike wrer already safe. The chancers will just print false documents. I've seen this with pulse oximeters. Bought one that was CE marked an had a notiifed body reference. On checking it turns out thet notified bod don't do pulse oximeters

Robert.

Exactly spot on, correct and already slowly being realised by the authorities.

One clear example was the Trading Standards seizing of approximately a thousand cheap chinese diesel air heaters. late last year. These heaters, while being cheap and likely without the best of instructions, were (IMO0) ‘satisfactory’ for the purpose for which they were designed - if used responsibly. They were offered as vehicle parking heaters, not for installing inside habitable buildings, which has become a popular use - according to the number of youtube videos on their use.

But lets agree, here, that lots of things are used for purposes they were not designed for. One example is the alarming number of knife-crime threats, injuries and deaths - using tools, designed for kitchen (or other legal applications) as weapons.

Thought "CE" meant Chinese Export on oriental offerings?

Regards Ian

Is it the particular metal body connectors used on that Chinese drive that you are not happy about Robert ?

All the Indramat, Siemens & Fanuc servomotors that use cable mounted connectors (rather than connecting boxes) I installed used metal body connectors.

Nigel B

Yes.
The connectors on the servodrives you used are designed for the purpose like these:
https://lapplimited.lappgroup.com/products/online-catalogue/products/epic-industrial-connectors/circular-connectors/epic-power-ls1/epic-power-ls1-d6.html
Note the range here:
https://lapplimited.lappgroup.com/products/online-catalogue/epic-industrial-connectors.html
includes power and signal variants.

The connector on the chinese unit are a type designed for low voltage DC. They date back to at least the 60's. A common applictaion was micropones on CB radios and the like.

Robert.

The connectors on the chinese motor control are sometiems called "aviation" connectors. This vendor
www.ebay.co.uk/itm/283143222904?
says they are rated for 400V and 10A. They may not break down at that but there is no engineered means of earthing the metal body of the free connector. They do not have a "make first break last" protective earth contact. They don't have the creapage and clearance distances required to meet international safety standards for >50V use.

To make thing worse. They have used a MALE connector on the OUTPUT to the motor. This means there are exposed pins with high voltage on them when the motor is unplugged. This is a serious shock risk.

Robert.