When Choosing a High-Quality Motor, you Must Focus on these 5 Key Points

How can we buy genuine motors at a fair price, and how to distinguish the quality of motors?

The three-phase asynchronous motor is a product with very mature technology, and the production threshold is also low. In areas with developed industrial chains, small workshop-style motor factories abound, but to achieve excellent performance and stable quality of the motor, it must be Only a large-scale motor factory where it can be guaranteed.

1.Silicon steel sheet

Silicon steel sheets are an important part of the motor, and together with copper wires account for the main cost of the motor. Silicon copper sheets are divided into cold-rolled steel sheets and hot-rolled steel sheets. The country has long advocated the abandonment of hot-rolled sheets. The performance of cold-rolled sheets can be reflected in the brand name. Generally, DW800, DW600, DW470, etc. are used. Ordinary asynchronous motors generally use DW800. Some companies use strip steel to manufacture motors, and the performance is significantly different.

2. Core length

Both the stator and rotor of the motor are die-cast from silicon steel sheets. The length and tightness of the die-casting have a great influence on the performance of the motor. The longer the die-casting length of the iron core is, the tighter it is, the better the power performance will be. Some companies reduce the cost by shortening the length of the iron core or reducing the price of the silicon steel sheet grade, and the price of the motor is lower.

3. Full rate of copper wire slot

The full rate of the copper wire slot refers to the amount of copper wire used. The longer the iron core, the more copper wire will be used at the same time. The enterprise reduces the slot shape of the stator without changing the length of the iron core, so as to reduce the amount of copper wire and reduce the cost.

4. Bearings

The bearing is the carrier that withstands the high-speed operation of the motor rotor. The quality of the bearing will affect the running noise and heat of the motor.

6. Craft

Including machining accuracy of parts, rotor die-casting process, assembly process, insulation dipping paint, etc., will affect the performance and quality stability of the motor. The production process of large-scale manufacturers is relatively stricter, and the quality is more guaranteed.

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Phase convertors certainly have been extensively discussed, but here's someones opinion on replacing 440 volt three phase motors-WHY? If your machines are wired for them, with magnetic starters that are functioning with the correct overload relays, why start from scratch?

If you don't have three phase power, that's so easily remedied Converting single phase to three phase is easily done, and getting a transformer to step up 220 to 440 is also not hard. Twenty five years ago, I was fortunate enough to have three phase service, so I was buying three phase woodworking machines without competition from the hobby homeowners. So I had an entire shop of machines. I eventually wanted to bring some home and run them in the basement of my house. At first I just used a 5 horsepower motor that I wrapped a rope around the shaft, pulled it quickly, and then switched it on. I instantly had a three phase power source good for three horsepower. Later I bought a 7 1/2 horsepower wide belt sander, and at that point got a 10 HP rotary phase convertor- WORKED GREAT. Paid $400.00 for a used one- so I had an ample supply of power. At some point I started buying quite a few machines wired for 440(460-480volts). At first I converted them back to 240, buying new heaters for the starters, crawling around the motors trying to read the wire numbers. Finally I figured enough, and bought an actual 240 to 480 step up transformer. When I ran a 480 volt motored machine, I'd switch on the convertor, and then just trip a circuit breaker to turn on the transformer. I had one receptacle wired right into the housing of the transformer, and I was set. Clean, safe, fused. Now why convert? If this is a hobby and you're anticipating buying more machines(isn't that our goal?), you'll never regret making the relatively small investment in creating your own three phase power, and stepping it up if necessary.

I now have two shops with 120 machines. I have three phase power but still use transformers to step up to 480 volts. Seems like half the machines I buy now, are wired 480. Saves a ton of time, just plugging them in and using them. To make sure I NEVER screw up with power though, I use all the CORRECT twistlock plugs. 220 Volt plugs on the 220 volt machines and 480 volt on the higher voltage machines. Even I forget sometimes what voltage my machines are wired. The correct plugs are literally a lifesaver. DON'T SCRIMP at this point. Twist locks are pretty expensive, but with a few key ebay buys, I'm swimming in them.

For a hobbyhomeowner in basement, I wouldn't say a three phase motor is a real advantage if you only have one. Certainly they are simpler, but for one motor the hassles of converting probably aren't worth it. It's when you want quite a few machines, and you want to buy them used, three phase is seen as a disadvantage. Most of the weekend warriors are gonna pass up three phase machines. So if you can run them, it gives you freedom to buy any machine. I haven't had a single phase or three phase motor burn out in 25 years. Although single phase motors have the addtional complexity of starter winding and the centrifigal switch, none of mine has died. When I buy a machine- frankly I don't care WHAT kind of motor is on when it's less than three horsepower. Above that, I prefer three phase. Draws less current per winding, which means smaller wire sizes to run it.

I can't even fathom why a dealer wouldn't sell a rotary phase converter. They're a proven commodity, that work great. I ran my entire shop with one for two years, until I sprung twenty grand to get the real deal. The only reason I needed to though, was I was getting machines with 20 and thirty horsepower motors. At that point, a rotary phase converter running on single phase 220 would practically eat up your entire 200 amps input.