The DC, permanent magnet, brushed electric motor is the workhorse of small, powered mechanical systems.
Examples are the small motor and the gear motor in the ME2011 Robot kit are shown below.
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Torque-Speed Curve
Motors have torque-speed curves.
For a fixed input voltage from a battery, the motor speed slows down as it is loaded.
With no load on the shaft (free-running), the motor runs at the no-load speed (NLS), the fastest possible speed for that voltage.
When the shaft is fully loaded and not allowed to move, the speed is zero and the motor is producing its stall torque (ST), the maximum possible torque.
(모터에서 stall은 Torque의 임계치를 의미한다.)
At stall torque, the current drawn out of battery is at its maximum, as is motor heating. Motors should be operated at stall only for brief periods of time (seconds) to save on batteries and to keep the motor from melting. The chart below shows an ideal motor torque-speed curve. The point labeled as the operating point indicates the speed the motor will run when driving a specific operating load. As that load changes, the operating point slides up and down the torque-speed curve.
모터뱅크에서 햇갈리게 구매하기 쉬운 모터드라이버 제품들
★잘못 기재한 spec을 보고 구매한 고객들에게 책임을 전가하므로 알아서 스팩을 찾아봐야한다.
DC Motor Driver DMD-50-SD :: 13200원 (SD=Single Direction)
DMD-50 :: 41800원 (쌍방향)
AC모터 Back EMF
220/380 Voltage라고 표기되어있다.
델타(Δ)결선 일경우 220V를 인가하면되고
와이(Y)결선 일경우 380V를 인가하면 된다.
델타결선 최종
★릴레이의 코일부분에 있는 GND는 Controller용 GND이고, 렐레이의 스위치 부분에 있는 GND는 220V용 GND이다.
맞는말이긴 하다. 하지만 그 GND를 하나로 합친다고 Controller가 damage를 입지는 않는다.
My problems had got solved now.I call my teacher today, he advises me to short the center tap transformer ground with the power supply ground.After doing so, I still didn't get the square wave, then I short the resistance, because the center tap transformer don't provide much current.It was a small transformer, so I thought may be 1kOhm resistor is too much for it and cannot provide the base current to the transistor.So I short the resistor, then I use the oscilloscope and with respect to ground (AC+DC) I checked the signal on the collector of the NPN transistor, there was a perfect square wave and a smile on my face :D
I don't understand the concept of shorting the AC ground with the DC ground, as why we do it and my another teacher while teaching us the circuit of microcontroller 8051 that was turning ON/OFF the electric bulb powered by 220V/50Hz through the help of RELAY.He said you don't short the 8051 GND with the Ground of the bulb.I don't remember the circuit, but it was something like this one.
