恒功率負載的機械特性較復雜，系統(tǒng)設計時應注意不能使異步電動機超過其同步轉(zhuǎn)速運行，否則易造成破壞性機械故障。通常變頻器的容量一般取1.1～1.5倍異步電動機的容量。
1.3 恒轉(zhuǎn)矩負載
在恒轉(zhuǎn)矩負載中，負載轉(zhuǎn)矩TL與轉(zhuǎn)速n無關(guān)，任何轉(zhuǎn)速下負載轉(zhuǎn)矩TL總保持恒定或基本恒定，負載功率則隨著負載速度的增高而線形增加。例如吊車、傳送帶、注塑機、攪拌機、提升機等摩擦類負載都屬于恒轉(zhuǎn)矩負載。這類負載采用變頻器控制的目的是實現(xiàn)設備自動化、提高勞動生產(chǎn)率、提高產(chǎn)品質(zhì)量。
變頻器拖動恒轉(zhuǎn)矩負載時，低速時的輸出轉(zhuǎn)矩要足夠大，并且要有足夠的過載能力，一般為150%額定電流。如果需要在低速下長時穩(wěn)速運行，應該考慮異步電動機的散熱能力，避免電動機溫升過高。
系統(tǒng)設計時應注意適當增大異步電動機的容量或增大變頻器的容量。變頻器的容量一般取1.1～1.5倍異步電動機的容量。
2、根據(jù)負載特性選取適當控制方式的變頻器
除變頻器制造工藝外，變頻器采用何種控制方式也是非常重要的。變頻器的控制方式主要分為開環(huán)控制和閉環(huán)控制兩種。其中開環(huán)控制方式，結(jié)構(gòu)簡單，性能可靠，但調(diào)速精度和動態(tài)反應性能較低；而閉環(huán)控制方式可以根據(jù)流量、溫度、位置、速度、壓力等參數(shù)的變化進行實時控制，動態(tài)反應快，但某些時候?qū)崿F(xiàn)起來比較困難，且成本較高。用戶應根據(jù)自身需求進行選擇相應的控制方式，從而獲得需要的調(diào)速特性。
.jpg)
(X5-8) 1 SMC VQ5200-3 SOLENOID VALVE X5-8
(6454) Gudel Vee Bar Roller Bearing FR35 (6454)
(T3-6) 1 ALLEN BRADLEY 100-K-5DJ10 MINI CONTACTOR.
(O4-3) 1 ALLEN BRADLEY 800MR-QA24GA PUSHBUTTON O4-3
(6132) Lot of 9 Bussmann Fuse Blocks CHCC1D 30A 600V .
(4837) Lot of 2 SMC Valves VSS8-8-FIG-D-3E?Z-V1 21-26VCo
(O4-3) 1 RED LION IFMR0036 SPEED SWITCH O4-3
(O4-3) 1 PASS&SEYMOUR PS330P6S P/S PLUG O4-3
(O4-3) 1 PASS&SEYMOUR PS330P6S P/S PLUG O4-3
(Q9-1) 6 IN BAG ENERPAC RC53K P14K RMC100K KITS Q9
(X1-1) 1 BANNER T30SP6FF400Q PHOTOELECTRIC SENSOR.
(3265) Allen Bradley Proximity Sensor 872C-A5C18-A5 (32
(4181)D Allen Bradley Potentiometer 800H-N102 Typ4,4X,1
(4260) Allen Bradley Overload Relay Block Rt Hand X-421
(4787)B Omron Photoelectric Switch E3X-DA11AT-S 12-24VD
(O1-8) 1 TELEMECANIQUE GV2-ME14 STARTER MANUAL O1-8
(R1-2) 1 CUTLER HAMMER E57-12LE06-C PROXIMITY SWITC
(R1-2) 1 CUTLER HAMMER E51SBL E51DS1
(2938) Helicoid 2284-0 0-200 Psi Pressure Gauge 4094
(6471)Versa Valve BSI-3309-P-316 0-200 Psi With Turn Kn
(H3) 1 NIB HONEYWELL MICRO SWITCH 1LS23 LIMIT SWITCH H3
(H4) 1 NIB MAC VALVES 6311D-000-PM-11?1DA SOLENOID VALVE
(H4) 1 NIB MAC VALVES 82A-AA-000-TM-D?AAP-2DA SOLENOID V
(H4) 1 NORDSON 105457 A PUMP SERVICE KIT H4
(O4-3) 1 ALLEN BRADLEY 871TM-DH2NP12-C?5 PROXIMITY S
(X1-1) 1 BANNER MIAD9D MINI-BEAM NAMUR. X1-1.
(X9-4) 1 NIB ROSS W1616B2020 SINGLE SOLENOID PILOT X9-4
(2487) 1 PARKER VALVE P/N L6954921153 (2487)
(1482) ALLEN BRADLEY 802F-TA60M11R-S?7 KEY INTERLOCK NIB
(2021) 1 SQUARE D SYMAX INPUT MODULE HIM131 (2021)
(7036) Siemens Auxiliary Switch A01JLD64 800 A Circuit
(4329) Trane Motor Terminal Kit p/n KIT12130 (4329)
(4332) Lot 3 Service First Contactor 30A 600V 3P CTR011
(Q3-5) 1 SHERLINE 0-5000 LB TRAILER TONGUE WEIGHT
(Q3-3) 1 SWAGELOK SS-QC8-B-8PM QUICK CONNECT BODY Q
(3677) Allen Bradley TTL Input Module PLC 5 1771-IG (36
(Q1-6) 1 KEYENCE PQ-01 PHOTOELECTRIC SENSOR WITH AM
(O1-10) 1 BARBER COLMAN AM-321-0-2 AUXILIARY SWITCH
(U1) 1 MARATHON ELECTRIC 7VH56T34F5304F FOUR IN ONE
(X5-13) 1 NIB JD GOULD COMPANY M 3V SOLENOID VALVE X5-1
(X5-15) 1 NIB EDWARDS ADAPTABEL 340-10N5 VIBRATING BELL
(PK-1) 1 VEEDER ROOT 744396-012 230VAC 6W COUNTER
(X5-14) 1 ALLEN BRADLEY 73A288 COIL FOR CONTACTOR
(X5-16) 1 OMRON E3S-DS5 PHOTOELECTRIC SWITCH X5-16
(O4-4) 1 MSD 219ABAP RELAY O4-4
(3879) Allen Bradley Oiltight Limit Switch 802T-A1 (3
(3885) Lot of 3 Pyle 30 Amp Receptacle 600 VAC 3P 250VD
(H2-1) 1 REDLION APLR0600 DISPLAY PANEL H2-1
(H2-2) 1 ALLEN BRADLEY 802A-E12M4-S7 SWITCH H2-2
(H2-2) 1 CUTLER HAMMER E51-SPL PHOTOELECTRIC SWITCH H2-
(O4-5) 1 PARKER B552ABH49C 3/8" VALVE O4-5
(4368) Durakool Mercury Switch G10Z-001 (4368)
(X6-1) 1 ALLEN BRADLEY 1771OA OUTPUT MODULE X6-1
(H3-3) 1 NIB ALLEN BRADLEY 140M-C2E-B40 MOTOR PROTECTOR
(1004) DURANT EATON COUNTER 6-YE-40724-400-?ERU
(8753) Crompton DC Amperes Meter 8963 262 DDVU Z4SFPQ01
(S1-1) 1 BAILEY NTCS02 TERMINATION MODULE. S1-1.
(N1-2) 1 NIB CUTLER-HAMMER E51RCP5 RECEPTACLE N1-2
(4450) Omron Proximity Switch TL-X10C1-GE 12-24 VDC 2M
.jpg)
在線客服