怎么洗保暖內(nèi)衣(完整版)
【正文】 ature winding ? Current = field current + armature current Speed constant independent of load up to certain torque Speed control: insert resistance in armature or field current DC motors (Rodwell Int. Corporation, 1999) 11 169。 UNEP 2023 Introduction ? Electromechanical device that converts electrical energy to mechanical energy ? Mechanical energy used to . ? Rotate pump impeller, fan, blower ? Drive pressors ? Lift materials ? Motors in industry: 70% of electrical load What is an Electric Motor? 3 169。 UNEP 2023 Introduction How Does an Electric Motor Work? (Nave, 2023) 1 2 3 4 4 169。 UNEP 2023 Type of Electric Motors Selfexcited DC motor: series motor DC motors (Rodwell Int. Corporation, 1999) ? Field winding in series with armature winding ? Field current = armature current ? Speed restricted to 5000 RPM ? Avoid running with no load: speed uncontrolled Suited for high starting torque: cranes, hoists 12 169。 UNEP 2023 Type of Electric Motors AC Motors – Induction motor ? Singlephase induction motor ? One stator winding ? Singlephase power supply ? Squirrel cage rotor ? Require device to start motor ? 3 to 4 HP applications ? Household appliances: fans, washing machines, dryers 20 169。 UNEP 2023 ? Motor load is indicator of efficiency ? Equation to determine load: Motor Load Load = Pi x ? HP x ? = Motor operating efficiency in % HP = Nameplate rated horse power Load = Output power as a % of rated power Pi = Three phase power in kW Assessment of Electric Motors 28 169。 UNEP 2023 Power Loss Area Efficiency Improvement 1. Fixed loss (iron) Use of thinner gauge, lower loss core steel reduces eddy current losses. Longer core adds more steel to the design, which reduces losses due to lower operating flux densities. 2. Stator I2R Use of more copper larger conductors increases cross sectional area of stator windings. This lower resistance (R) of the windings reduces losses due to current flow (I) 3 Rotor I2R Use of larger rotor conductor bars increases size of cross section, lowering conductor resistance (R) losses due to current flow (I) 4 Friction Winding Use of low loss fan design reduces losses due to air movement 5. Stray Load Loss Use of optimized design strict quality control procedures minimizes stray load losses (BEE India, 2023) Use Energy Efficient Motors Energy Efficiency Opportunities 36 169。 UNEP 2023 Energy Efficiency Opportunities Checklist to maintain motor efficiency ? Inspect motors regularly for wear, dirt/dust ? Checking motor loads for over/under loading ? Lubricate appropriately ? Check alignment of motor and equipment ? Ensure supply wiring and terminal box and properly sized and installed ? Provide adequate ventilation 7. Maintenance 44 169。 UNEP 2023 Energy Efficiency Opportunities ? Variable speed drives (VSDs) ? Also called inverters ? Several kW to 750 kW ? Change speed of induction motors ? Can be installed in existing system ? Reduce electricity by 50% in fans and pumps ? Conver
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1