Showing posts with label speed. Show all posts
Showing posts with label speed. Show all posts
Friday, January 10, 2014
Motor Speed Control
This circuit will allow you to control the speed of an AC motor, for example an electric drill. The way that this circuit works is as follows. The bridge rectifier produces dc voltage from the 120vac line. A portion on this current passes through the 10K ohm pot. The circuit comprised of the 10k pot, the two 100 ohm resistors and the 50uf capacitors delivers gate drive of the SCR. The diode D1 protects the circuit from reverse voltage spikes. The ratings of the bridge rectifier and the SCR should be 25 amps and PIV 600 volts. The diode D1 should be rated for 2 amps with PIV of 600 volts. The circuit can handle a load up to 10 amps. The SCR should be very well heat sinked.
Read the rest entry[...]
Monday, July 8, 2013
4A High Speed Low Side Gate Driver
The UCC27518 and UCC27519 single-channel, high-speed, low-side gate driver device is capable of effectively driving MOSFET and IGBT power switches. Using a design that inherently minimizes shoot-through current, UCC27518 and UCC27519 are capable of sourcing and sinking high, peak-current pulses into capacitive loads offering rail-to-rail drive capability and extremely small propagation delay typically 17 ns.
The UCC27518 and UCC27519 provide 4-A source, 4-A sink (symmetrical drive) peak-drive current capability at VDD = 12 V. The UCC27518 and UCC27519 are designed to operate over a wide VDD range of 4.5 V to 18 V and wide temperature range of -40°C to 140°C. Internal Under Voltage Lockout (UVLO) circuitry on VDD pin holds output low outside VDD operating range.
4A High-Speed Low-Side Gate Driver Circuit diagram:
Features:
Device Uses:
The UCC27518 and UCC27519 provide 4-A source, 4-A sink (symmetrical drive) peak-drive current capability at VDD = 12 V. The UCC27518 and UCC27519 are designed to operate over a wide VDD range of 4.5 V to 18 V and wide temperature range of -40°C to 140°C. Internal Under Voltage Lockout (UVLO) circuitry on VDD pin holds output low outside VDD operating range.
4A High-Speed Low-Side Gate Driver Circuit diagram:
Features:
- Low-Cost, Gate-Driver Device Offering Superior Replacement of NPN and PNP Discrete Solutions
- Pin-to-Pin Compatible With TI’s TPS2828 and the TPS2829
- 4-A Peak Source and 4-A Peak Sink Symmetrical Drive
- Fast Propagation Delays (17-ns typical)
- Fast Rise and Fall Times (8-ns and 7-ns typical)
- 4.5-V to 18-V Single Supply Range
- Outputs Held Low During VDD UVLO (ensures glitch free operation at power-up and power-down)
- CMOS Input Logic Threshold (function of supply voltage with hysteresis)
- Hysteretic Logic Thresholds for High Noise Immunity
- EN Pin for Enable Function (allowed to be no connect)
- Output Held Low when Input Pins are Floating
- Input Pin Absolute Maximum Voltage Levels Not Restricted by VDD Pin Bias Supply Voltage
- Operating Temperature Range of -40°C to 140°C
- 5-Pin DBV Package (SOT-23)
Device Uses:
- Switch-Mode Power Supplies
- DC-to-DC Converters
- Companion Gate Driver Devices for Digital Power Controllers
- Solar Power, Motor Control, UPS
- Gate Driver for Emerging Wide Band-Gap Power Devices (such as GaN)
Friday, July 5, 2013
Junk box Fan Speed Controller
My new home theatre receiver was getting rather hot in the close confines of its cabinet, with the temperature reaching over 40°C after only about 30 minutes of use. To help lower the temperature, I decided to install a fan in the cabinet. A 75mm hole was cut in the shelf under the receiver, and a 12V fan salvaged from an old computer power supply was mounted underneath. The fan was powered from a 12V DC plugpack.
This did the job, keeping the temperature below 30°C even after prolonged use on a warm day. However, the fan was annoyingly loud when running at full speed. To reduce the noise level substantially, I built this fan speed controller with temperature feedback. The circuit was culled from variety of ideas found on various sites on the internet, with the final circuit designed from what was in the "junk box". Air temperature in the cabinet is sensed via an LM335 (TS1).
Circuit diagram:
Junk-box Fan Speed Controller Circuit Diagram
It is glued to a piece of aluminium about 25mm square with instant glue, which is then attached to the top of the receiver with "Blue-Tack". About 300mm of audio coax makes the connection back to the circuit board. The LM335’s output rises 10mV per degree Centigrade. It is calibrated to zero output at -273°C, so at 20°C, the output will be 2.93V. This is applied to the non-inverting input of a 741 op amp (IC1). A 1N4733 5.1V Zener diode provides a voltage reference for the inverting input via trimpot VR1. The output of the op amp drives a TIP122 Darlington transistor (Q1), which in turn drives the fan motor. The op amp gain was calculated to give about 12V to the fan at 40°C.
To keep the transistor cool, it is mounted on the metal base of a small plastic box, which is also used to house the components. Initial setup should be performed with everything turned off and the ambient temperature at about 20°C. Adjust the 10-turn pot until the fan just stops running. I used a gasket made from foam strips and "blue-tacked" them between the feet of the receiver to direct all of the airflow through it. The temperature now remains at about 32°C, the fan runs very quietly and continues to run down for about 30 minutes after the receiver is switched off.
Source by : Streampowers
Subscribe to:
Posts (Atom)