Minggu, 25 Desember 2011

Voltage Impulses

Forms of Voltage Impulses

There are three forms inpuls voltage that may be experienced in the electric power system, namely:
1. Lightning impulse voltage
2. Surge impulse voltage circuit
3. Truncated impulse voltage

Wavefronts are part of a wave that starts from point zero (nominal) to the point of peak (according to IEC determined from the nominal point of intersection between the axis of time with the straight line connecting the 30% and 90% of peak voltage). While the tail is part of the wave peak to wave down 50% from the peak point. The wave form is expressed as:
± (x Tt Tf) ms. [IEC: ± (1.2 x 50) ms]

Circuit used for surge value:
[IEC: ± (250 x 2500) ms]
Tools that can be used to generate a high voltage impulse among others:
1. RC impulse generators
2. Impulse generator RLC
3. Marx Generator
5. How to Measure Voltage Impulse

a. Using Sela Ball

Sela ball is often used to measure the impulse voltage. Sela ball must always ditera with voltage spark between the ball 50% of the standard. Sela standard ball is a ball broke in qualifying standards regarding:
1. Quality
2. The distance between
3. The size of the ball

In certain circumstances the air, between the ball always has a certain spark voltage as well. That is why the sidelines ball can be used as a measuring tool.

Form of the condition of the ball electrode
1. Its surface is slippery
2. Flat arches
3. The surface of the ball must be free of dust, oil, etc.
4. Prisoners damper installed in series with the minimum distance 2d
(D = diameter) of the ball is measured from the point where there is a spark.
a. The test voltage ac = 100 kW s / d 1000 kW
b. Impulse test voltage 500 W

b. Using a CRO

By using Chatode-Ray Oscillograph (CRO) we can:
- Voltage peak
- Waveform
- The lack of impulse shape abnormalities (describing damage to test equipment)
CRO can only measure a low voltage only, so to measure the high voltage required voltage divider (either resistors or capacitors)
READ MORE - Voltage Impulses

switching power supply

C1, 2 : 100nF, 250VAC polypropylene (RS 190-8539)
C3 : 680uF, 450V electrolytic
C4, 5, 6, 7, 8, 9, 10, 11 : 470nF, 630V polypropylene
C12, 13 : 1uF, 50V ceramic multilayer (RS 126-067)
C14 : 3.3nF, 1.6kV polypropylene
C15, 16 : 10nF, 250VAC polypropylene (RS 190-8472)
C17, 18, 19, 20, 21, 22 : 1000uF, 25V low ESR electrolytic (RS 105-997)
C23, 24 : 2200uF, 16V low ESR electrolytic (RS105-947)
C25, 26, 27, 28, 29, 30 : 100nF, 50V ceramic
C31 : 470nF, 50V ceramic multilayer
C32 : 22uF, 50V electrolytic
C33 : 10uF, 50V electrolytic
C34 : 1uF, 50V electrolytic
C35 : 33nF, 50V polyester
C36 : 4.7nF, 50V polyester
C37 : 330nF, 50V polyester or ceramic multilayer
C38 : 100uF, 10V electrolytic
D1 : Rectifier bridge, 1kV, 8A. GBPC810 or similiar.
D2, 4, 17 : Ultrafast diode, 1kV, 1A. UF4007 or similiar. Lower
voltage (down to 100V) is acceptable.
D3, 5 : Ultrafast diode 1kV, 3A. UF5408 or similiar.
D6, 7, 8, 9 : Dual Schottky diode, 100V, 30A total. PBYR30100CT
or similiar. Single diode would also be suitable.
D10, 11, 12, 13, 14, 15, 16, 18 : 1N4148 switching diode
FB1, 2 : Amidon FB-73-801 ferrite bead, slipped over wire.
FB3..14 : Amidon FB-73-2401 ferrite beads, slipped six each
over the two 13.8VDC output cables.
L1 : Common mode choke, 8mH each winding, 6A.
I used junk box specimen. RS 288-159 is suitable.
L2: : 20uH, 60A choke. 15 turns on Amidon T-157-26
toroid. Wound with ten #16 enameled wires
in parallel.
L3: : 5uH (uncritical), 60A choke. 10 turns on ferrite solenoid,
10mm diameter, 50mm long. Wound with two #11
wires in parallel.
LED1 : Dual LED, green-red, common cathode
M1 : 12V 5W brushless DC fan, 120 x 120 x 25mm
NTC1, 2 : Inrush current limiter, 2.5R cold resistance (RS 191-2005)
P1 : CEE-22 male connector with integrated fuse holder
and EMI filter, 250VAC, 6A, (RS 210-291)
Q1, 2 : High voltage switching transistor, BUH1215 or similiar.
Must resist at least 400Vceo , and maintain a
beta of over 12 at a current level of 8A. (RS 859-874)
Q3, 4 : BC639-16 transistor. Must resist 100V and 0.5A.
Q5 : BD683 darlington transistor
R1, 5 : 10R, 5W low inductance preferred
R2, 6 : 180kR, 0.5W carbon
R3, 7, 19 : 1R, 1W carbon
R4, 8 : 2,7kR, 0.25W carbon
R9 : 47R, 5W low inductance preferred (induktansi rendah)
R10, 11 : 1.8R, 2W low inductance preferred (induktansi rendah)
R12 : 180R, 0.5W carbon
R13 : 3.3kR, 0.25W carbon
R14 : 1.5kR, 0.5W carbon
R15, 16 : 3.9kR, 0.25W carbon
R17, 18, 32, 33, 36, 38 : 1kR, 0.25W carbon
R20 : 22R, 0.5W carbon
R21, 22, 23, 24 : 4.7kR, 0.25W carbon
R25, 27, 29 : 22kR, 0.25W carbon
R26 : 4.3kR, 0.25W carbon
R28 : 13kR, 0.25W carbon
R30 : 12kR, 0.25W carbon
R31 : 10kR, 0.25W carbon
R34 : 1MR, 0.25W carbon
R35, 37 : 27kR, 0.25W carbon
R39 : 33R, 2W carbon
SW1 : 2-pole power switch, 250VAC, 10A
T1 : Primary 15 turns, secondary 2+2 turns. Wound with
copper foil and mylar sheet. Uses four Amidon
EA-77-625 ferrite E-cores (8 halves). Equivalents
include Thomson GER42x21x15A, Phillips 768E608,
TDK EE42/42/15. See text for winding instructions.
T2 : Secondary is 100+100 turns #36 enamel wire. Primary
is one turn #15 plastic insulated cable, wound on
secondary. Wound on Amidon EE24-25-B bobbin. Uses an
Amidon EA-77-250 core. Equivalents are Thomson
GER25x10x6, Phillips 812E25Q, TDK EE25/19.
T3 : Control winding is 26+26 turns #27 enamel wire.
Base windings are 8 turns #20 each. Collector winding
is one turn #15 plastic insulated cable. Bobbin and
core like T2. See text.
U1 : Pulse width modulator IC, LM3524, SG3524, UC3524 or
U2 : Quad single supply operational amplifier, LM324
or similar.
U3 : 5V voltage reference, LM336Z-5.0 or similiar.
VR1, 2, 3 : 1kR PCB mounted trimpot

Project design switching power supply has a very large power capability. This power supply produces 13.8V output, the continuous load currents up to 40A. If the potentiometers are set, then the power supply can deliver up to 60A .. Ripple voltage at the output is about 20mV, and its efficiency is 88%. A cooling fan operates depending on the time-average power used, and the LED indicator to tell if the voltage is normal, too high or too low. And Power Supply that has great power kamampuan is just a small form in the box that measures just 306 x 150 x 130mm, including all projections, and weighs only 2.8kg!

Description of Series
Line voltage through CEE-22 connector through the fuse and EMI filter (P1). Then passed through a 2-pole power switch, and again through the line filter to remove noise (C1, L1, C2). Two NTC resistors limit the inrush. A bridge rectifier provides power to large electrolytic capacitor (C3), who works at 300VDC. Power oscillator formed by Q1, Q2, and by beberaa other components, and feedback and control transformer (T3). T2 and related components act as the primary current sensors. T1 is the power transformer, providing about 20 Volt Schottky rectifier wave into the box (D6. 9). A toroidal inductor (L2) and six elekrtolit parallel capacitors provide a low resistance value equivalent forms of the main filter, while the L3 and C23 .. 24 is just there to reduce the additional riple. 13.8V is connected to the output through a series of ferrite beat with some small decoupling capacitors are mounted directly on the output terminals.
Control circuit is IC 3524 (U1), driven by the auxiliary rectifier (D17). This IC contains a voltage reference, oscillator, pulse width modulator (PWM), an error amplifier, current sense amplifier, flip-flop and the driver circuit. The sensor output voltage and current level sensors, through transistors Q3 and Q4 controls the power oscillator. C37, C35 and R23 are used to implement PID (proportional-integral-derivative) control loop response in full.
A quadruple operational amplifier (U2) is used for two purposes aids: To control the cooling fan according to the average level of current, voltage and LED indicators for steering three colors: green light if the voltage is OK, orange if the voltage is too low and the red if too high.
READ MORE - switching power supply

Kamis, 22 Desember 2011


TOSHIBA Bipolar Digital Integrated Circuit Silicon Monolithic
• General-Purpose Linear ICs
• 7-ch Darlington Sink Driver
• Darlington Drivers IC
• The ULN2004APG/AFWG Series are high−voltage, high−current darlington drivers comprised of seven NPN darlington pairs. All units feature integral clamp diodes for switching inductive loads. Applications include relay, hammer, lamp and display (LED) drivers. The suffix (G) appended to the part number represents a Lead (Pb)-Free product.
• Features: [1] Output current(single output): 500mA(max). [2] High sustaining voltage output: 50V(min). [3] Output clamp diodes. [4] Inputs compatible with various types of logic. [5] Package Type-APG: DIP-16pin. [6] Package Type-AFWG: SOL-16pin.
• Output Sustaining Voltage(VCE)(sus): 50V
• Output Current(Iout): 500mA
• Recommended Input Voltage: 6V to 15V
• Clamp Diode Reverse Voltage(VR): 50V
• Clamp Diode Forward Current(IF): 500mA
• Input Base Resistor: 10.5kΩ
• Number of Drivers / Receivers: 7 / 0
• Linear ICs Type: Darlington Transistor Array
• Number of Arrays: 7
• Transistor Polarity: NPN
• Input Compatibility: PMOS, CMOS
• Operating Temperature Range(Topr): -40°C to +85°C
• Storage Temperature Range(Tstg): -55°C to +150°C
• Brand Name: TOSHIBA
• Lead-Free Type
• RoHS Compliant
• Mounting Type: Through Hole / DIP(Dual in -line package)
• Package Type: DIP16
• Lead Count: 16
• Packing: 25 units / tube
• Mass stock on-hand merchandise supply
• We supply various electronic components and welcome your inquiries