Variable-frequency drive (VFD) is a power control device that controls the AC motor by changing the working frequency of the motor by applying variable frequency technology and microelectronic technology. The switching power supply circuit provides the control power of the inverter, which is a prerequisite for the normal operation of the inverter. To repair the inverter, you must first understand the switching power supply circuit.
The switching power supply circuit used in the frequency converter is a straight-through type inverter circuit. It is a voltage and power converter that converts the DC voltage and power into a pulse voltage and rectifies it into another DC voltage. The input and output voltages are isolated by the switching transformer, and the switching transformer functions as a power transfer and voltage/current conversion. The switching transformer is a step-down transformer. The characteristics of the switching power supply are as follows:
1) The oscillation and voltage regulation mode of the switching power supply is to adjust the output voltage by changing the pulse width or period. It is called time proportional control, and is divided into PWM (width adjustment) and PFM (frequency modulation) control modes.
2) From the energy conversion characteristics of the circuit, it can be divided into two working modes: forward and reverse. When the switch tube is saturated and turned on, the rectifier connected to the secondary winding is turned off by the reverse bias, and the primary winding of the switching transformer flows into the current to store energy (electromagnetic conversion). When the switch tube is turned off, the secondary winding discharges electric energy (magnetoelectric conversion) through the load circuit. The positive mode is the opposite, and there are not many practical applications.
3) From the primary circuit structure of the switching transformer, there are two circuit forms composed of discrete components and integrated oscillating chips. Therefore, from the source of the oscillating signal, it is divided into self-excited (discrete parts) and other exciter (IC circuit) switching power supply. Both circuit configurations have applications.
4) The switch tube has a bipolar device and a field effect transistor.
5) Small-power inverters use single-ended forward-excited circuits, and large- and medium-power inverters often use double-ended forward circuits. Generally, the switching power supply of the inverter often provides the following voltage outputs: CPU and auxiliary circuits, control circuit, +5V power supply for operation display panel; ±15V power supply for fault detection circuit and control circuit such as current, voltage and temperature; control terminal 24V power supply for working relay coils. The four-way isolated power supply is about 22V. The four-way power supply is often processed by the voltage regulator circuit into +15V, -7.5V positive and negative power supplies for the drive circuit to provide excitation current for the IGBT inverter output circuit. .
In any electronic device, the failure rate of the power circuit is always quite high because it has to provide the power supply of the whole machine, and the burden is the heaviest. The switching power supply circuit of the frequency converter is simple in form and simple in structure. But simple circuits can also cause troubles. The maintenance of the switching power supply is not as intuitive as the linear power supply. Any abnormality in the oscillation, voltage regulation, protection, load, etc. of the circuit will cause various faults in the circuit.
No response after power-on, no display on the operation display panel, the inverter does not seem to be powered. The control voltage of the measurement control terminal and the 10V frequency adjustment voltage are both 0. It is normal to measure the resistance of the main terminal of the inverter, so it can be concluded that the problem is in the switching power supply circuit.
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Label: Inverter switching power supply common sense analysis
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Dimension
1/2" to 4"(DN15~DN100)
Range(Wall Thickness):
3000LB to 9000LB
XS, Sch80, Sch160, XXS.
Standard
ASME/ANSI B16.11
MSS SP-79, MSS SP-83, MSS SP-114
JIS B2316, JIS B2302 etc.
Material:
General Stainless steel, Super Stainless Steel, Duplex Stainless Steel (Ferritic-Austenitic Stainless Steel), Austenitic Stainless Steel, Martensitic Stainless Steel, Ferritic Stainless Steel. etc.
Material:
Carbon steel:
ASTM A105;
ASTM A266 GR.1,GR.2,GR.3,GR.4
Stainless steel:
304/SUS304/UNS S30400/1.4301
304L/UNS S30403/1.4306;
304H/UNS S30409/1.4948;
309S/UNS S30908/1.4833
309H/UNS S30909;
310S/UNS S31008/1.4845;
310H/UNS S31009;
316/UNS S31600/1.4401;
316Ti/UNS S31635/1.4571;
316H/UNS S31609/1.4436;
316L/UNS S31603/1.4404;
316LN/UNS S31653;
317/UNS S31700;
317L/UNS S31703/1.4438;
321/UNS S32100/1.4541;
321H/UNS S32109;
347/UNS S34700/1.4550;
347H/UNS S34709/1.4912;
348/UNS S34800;
Alloy steel:
ASTM A694 F42/F46/F48/F50/F52/F56/F60/F65/F70;
ASTM A182 F5a/F5/F9/F11/F12/F22/F91;
ASTM A350 LF1/LF2/LF3;
Duplex steel:
ASTM A182 F51/S31803/1.4462;
ASTM A182 F53/S2507/S32750/1.4401;
ASTM A182 F55/S32760/1.4501/Zeron 100;
2205/F60/S32205;
ASTM A182 F44/S31254/254SMO/1.4547;
17-4PH/S17400/1.4542/SUS630/AISI630;
F904L/NO8904/1.4539;
725LN/310MoLN/S31050/1.4466
253MA/S30815/1.4835;
Nickel alloy steel:
Alloy 200/Nickel 200/NO2200/2.4066/ASTM B366 WPN;
Alloy 201/Nickel 201/NO2201/2.4068/ASTM B366 WPNL;
Alloy 400/Monel 400/NO4400/NS111/2.4360/ASTM B366 WPNC;
Alloy K-500/Monel K-500/NO5500/2.475;
Alloy 600/Inconel 600/NO6600/NS333/2.4816;
Alloy 601/Inconel 601/NO6001/2.4851;
Alloy 625/Inconel 625/NO6625/NS336/2.4856;
Alloy 718/Inconel 718/NO7718/GH169/GH4169/2.4668;
Alloy 800/Incoloy 800/NO8800/1.4876;
Alloy 800H/Incoloy 800H/NO8810/1.4958;
Alloy 800HT/Incoloy 800HT/NO8811/1.4959;
Alloy 825/Incoloy 825/NO8825/2.4858/NS142;
Alloy 925/Incoloy 925/NO9925;
Hastelloy C/Alloy C/NO6003/2.4869/NS333;
Alloy C-276/Hastelloy C-276/N10276/2.4819;
Alloy C-4/Hastelloy C-4/NO6455/NS335/2.4610;
Alloy C-22/Hastelloy C-22/NO6022/2.4602;
Alloy C-2000/Hastelloy C-2000/NO6200/2.4675;
Alloy B/Hastelloy B/NS321/N10001;
Alloy B-2/Hastelloy B-2/N10665/NS322/2.4617;
Alloy B-3/Hastelloy B-3/N10675/2.4600;
Alloy X/Hastelloy X/NO6002/2.4665;
Alloy G-30/Hastelloy G-30/NO6030/2.4603;
Alloy X-750/Inconel X-750/NO7750/GH145/2.4669;
Alloy 20/Carpenter 20Cb3/NO8020/NS312/2.4660;
Alloy 31/NO8031/1.4562;
Alloy 901/NO9901/1.4898;
Incoloy 25-6Mo/NO8926/1.4529/Incoloy 926/Alloy 926;
Inconel 783/UNS R30783;
NAS 254NM/NO8367;
Monel 30C
Nimonic 80A/Nickel Alloy 80a/UNS N07080/NA20/2.4631/2.4952
Nimonic 263/NO7263
Nimonic 90/UNS NO7090;
Incoloy 907/GH907;
Nitronic 60/Alloy 218/UNS S21800
SALES@GHSAILINGPIPE.COM
SALES@GHSAILINGPIPE.COM
The boss, also known as the nozzle, is a disposable component of the automatic control instrument in the process piping, which is used to connect the supervisor and other components.
The single side double point welding of the convex platform has the following advantages: relatively low cost, multiple use of fixed equipment or robot welding; the surface deformation is slight, the quality is relatively stable; the welding efficiency is high, and the welding work of two welding can be completed at a time. The shortcoming is that there is a certain amount of grinding at the time.
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