怎么洗保暖內(nèi)衣(編輯修改稿)
2025-01-19 04:45 本頁面
【文章內(nèi)容簡介】 apabilities ? 1/3 to hundreds HP applications: pumps, pressors, conveyor belts, grinders ? 70% of motors in industry! 21 169。 UNEP 2023 Type of Electric Motors AC Motors – Induction motor Speed and slip ? Motor never runs at synchronous speed but lower “base speed” ? Difference is “slip” ? Install slip ring to avoid this ? Calculate % slip: % Slip = Ns – Nb x 100 Ns Ns = synchronous speed in RPM Nb = base speed in RPM 22 169。 UNEP 2023 Type of Electric Motors AC Motors – Induction motor Relationship load, speed and torque At start: high current and low “pullup” torque start high At 80% of full speed: highest “pullout” torque and current drops At full speed: torque and stator current are zero 23 169。 UNEP 2023 Training Agenda: Electric Motors Introduction Types of electric motors Assessment of electric motors Energy efficiency opportunities 24 169。 UNEP 2023 Assessment of Electric Motors Motors loose energy when serving a load ? Fixed loss ? Rotor loss ? Stator loss ? Friction and rewinding ? Stray load loss Efficiency of Electric Motors (US DOE) 25 169。 UNEP 2023 Factors that influence efficiency ? Age ? Capacity ? Speed ? Type ? Temperature ? Rewinding ? Load Efficiency of Electric Motors Assessment of Electric Motors 26 169。 UNEP 2023 Motor part load efficiency ? Designed for 50100% load ? Most efficient at 75% load ? Rapid drop below 50% load Efficiency of Electric Motors (US DOE) Assessment of Electric Motors 27 169。 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 Three methods for individual motors ? Input power measurement ? Ratio input power and rate power at 100% loading ? Line current measurement ? Compare measured amperage with rated amperage ? Slip method ? Compare slip at operation with slip at full load Motor Load Assessment of Electric Motors 29 169。 UNEP 2023 Input power measurement ? Three steps for threephase motors Step 1. Determine the input power: Motor Load Pi = Three Phase power in kW V = RMS Voltage, mean line to line of 3 Phases I = RMS Current, mean of 3 phases PF = Power factor as Decimal 10003xPFxIxVPi ?Assessment of Electric Motors 30 169。 UNEP 2023 Input power measurement Step 2. Determine the rated power: Step 3. Determine the percentage load: Motor Load rr xhpP ??%100xPPiLoadr?Load = Output Power as a % of Rated Power Pi = Measured Three Phase power in kW Pr = Input Power at Full Rated load in kW Pr = Input Power at Full Rated load in kW hp = Name plate Rated Horse Power ?r = Efficiency at Full Rated Load Assessment of Electric Motors 31 169。 UNEP 2023 Result 1. Significantly oversized and underloaded 2. Moderately oversized and underloaded 3. Properly si
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