ALLEN BRADLEY 2711-B5A8
異步電機(jī)產(chǎn)生電磁轉(zhuǎn)矩,必需的轉(zhuǎn)差s,在電機(jī)轉(zhuǎn)速較高的情況下,比如額定轉(zhuǎn)速,s約3%,其影響可忽略。在變頻器變頻運(yùn)行時,為產(chǎn)生同樣的電磁轉(zhuǎn)矩,s反比于同步頻率,隨著同步頻率的下降,s越來越大;當(dāng)同步頻率低到程度時電機(jī)可能會停止轉(zhuǎn)動,也就是轉(zhuǎn)差s在低速時嚴(yán)重影響電機(jī)調(diào)速的精度。
由電機(jī)學(xué)原理可知,異步電機(jī)的機(jī)械特性在電磁轉(zhuǎn)矩(TL)小于大轉(zhuǎn)矩(Tm)時,不同同步轉(zhuǎn)速下的機(jī)械特性近似為一組平行線,也就是說為產(chǎn)生同樣的電磁轉(zhuǎn)矩,在不同同步頻率下其速度降落基本相同,這就是轉(zhuǎn)差補(bǔ)償?shù)某霭l(fā)點(diǎn)。當(dāng)同步頻率為f0時,為輸出T0的轉(zhuǎn)矩,速度降落為△f,為了保證電機(jī)轉(zhuǎn)速f0,就要將同步頻率提高到f0+△f。
轉(zhuǎn)差補(bǔ)償目的是要提高電機(jī)機(jī)械特性的硬度,準(zhǔn)確進(jìn)行轉(zhuǎn)差補(bǔ)償,這需要知道轉(zhuǎn)差和電磁轉(zhuǎn)矩之間的函數(shù)關(guān)系。在恒Er/f1控制方式下,電機(jī)機(jī)械特性是直線,因此轉(zhuǎn)差與電磁轉(zhuǎn)矩成線性關(guān)系,即在保持轉(zhuǎn)子磁通幅值不變的條件下,電磁轉(zhuǎn)矩與轉(zhuǎn)差頻率成正比。在恒U1/f1控制和恒Eg/f1控制下,電磁轉(zhuǎn)矩與轉(zhuǎn)差頻率成非線性關(guān)系,但是在電磁轉(zhuǎn)矩(TL)比大轉(zhuǎn)矩(Tm)小得多時,電磁轉(zhuǎn)矩與轉(zhuǎn)差頻率成近似線性關(guān)系,只是恒Eg/f1控制的近似線性段更長,而且由于恒Eg/f1控制在各同步頻率下的大轉(zhuǎn)矩(Tm)不變,因此,這種近似關(guān)系也不會隨同步頻率變化而變化。因此,在補(bǔ)償定子電阻降落(IR降),保持Eg/f1恒定的情況下,通常采用與恒Er/f1控制方式下相同的線性補(bǔ)償方法。
ALLEN BRADLEY 2711-B5A8
Toshiba ARNI-910G-CT PCB Driver Board ARNI910GCT
ITE Gould 5600 Fused Sz Size 3 A203E MCC Bucket 100A
Cutler Hammer CH Advantage W201KHCF Size 6 Contactor
Allen-Bradley AB 500-AOD93 Contactor 500-A0D93
Cutler Hammer Unitrol Size 1 Reversing MCC Bucket 7 Amp
Square D I-Line Circuit Breaker FC34040 40Amp A 40 Amp
Square D I-Line Circuit Breaker FC34040 40Amp A 40 Amp
GE General Electric Spectra THED136090 90 Amp 90A A
Westinghouse Advantage W201KHCF Sz. 6 Reverse Contactor
Siemens ITE Sentron Breaker NXD63B120 1200A 1200 Amp A
GE Fanuc IC600CB526 Logic Control Rev N, P
Asea CLMD63 C2 Capacitor 20 KVAR LVNQ 480V CLMD 63 ABB
Foxboro E83F-08S1KSIR-AJ Vortex Flowmeter E83F NEW
Square D PFA34020 20 Amp Plug-In Busway Unit Bus Plug
General Electric GE THFP362 / THFP363 Switch 60 100 Amp
Allen Bradley 2711E-T12C6 AB PanelView 1200e 2711ET12C6
General Electric DC Motor 50 HP 1750/2100 RPM CD365AT
ITE Gould 5600 Breaker Size 3 8502SEO MCC Bucket 100A
Westinghouse Panelboard Switch FDPS324R 200 Amp A FDP
GE Spectra ADS32030HD Fuse Panelboard Switch 30 A 240V
Hitran Transformer 34 kVA 460/460Y/266 V 34kVA 3 PH Y
Westinghouse Mark 75 HKL3400F 350Amp 350A 350 A Amp
Siemens RV361G 30 Amp Busway Plug Unit Bus Switch NIB
General Electric DC Motor 30 HP 1750/2300 RPM CD366AT
CH Westinghouse HLDB HLDB3600FT33W 600 Amp 600A A
Federal Pacific QMQB1036 Panelboard Switch 100 A QMQB
Federal Pacific QMQB2036 Panelboard Switch 200 A QMQB
Foxboro I/A P0800DA 10 FT Fieldbus Block Cable P0800 DA
Acme Transformer 20 kVA 460/460Y266 V 3 PH 20kVA 3R Y
Cutler Hammer Eaton Sz 0 Fuse AN16BN0 Combo Starter Box
DuPont 571001 5700 Moisture Analyzer Du-Pont
Daykin GPFS-03 L O Transformer Disconnect Switch 1.5kVA
Telemecanique Altivar 71 ATV71HU30M3 AC Drive 4HP/3kW
Cutler Hammer Westinghouse HFD3015 15A A 15 Amp w/Aux.
Square D Circuit Breaker FAL36020 20 Amp 20Amp 20A A
Sharp ZW-32N2T Input Unit DC 12/24V ZW32N2T 32 N 2 T
Westinghouse Panelboard Switch FDPS364 200 Amp A FDP
Honeywell 8476-981-065-A-4 Digital Indicator: NEW
Square D I-Line NA361000 NA-361000 NA 1000 Amp 1000A A
Keyence BL-U1 Bar Code Reader Controller 100~240V BLU1
Square D I-Line NC361200 NC-361200 NA 1200 Amp 1200A A
Siemens SBS 5050 SBS5050 SBS5050F 5000 Amp SB50TP02G
Siemens SBH 5050 SBH5050 SBH5050F 5000 Amp SB50TP02G
Sick MSLS02-25011 MSL Safety Photoelectric Switch
Siemens SBS 5050 SBS5050 SBS5050DV 5000 Amp SB50TP02G
Siemens SBH 5050 SBH5050 SBH5050DV 5000 Amp SB50TP02G