I. Introductionof Electric Fast Transient Generator
The electric fast transient (EFT) is a phenomenon that occurs within electrical circuits. When an inductive load is disconnected, transient disturbances are generated at the disconnection point due to contactor clearance insulation breakdown or arcing. If the inductive load is repeatedly switched on and off, these pulse bursts will recur. Although the power of individual transient disturbances is typically small and unlikely to cause immediate damage, their wide spectral distribution can pose a threat to the reliability of electrical and electronic equipment. Thence, the electrical fast transient generator is crucial.
The Pego electrical fast transient generator is to simulate the electrical fast transient or burst caused by switching transients (interruption of inductive loads, relay contact bounce, etc.), the repetitive fast transient test is a test with bursts consisting of a number of fast transients, coupled into power supply, control, signal and earth ports of electrical and electronic equipment. The EFT/B generator can meet the test requirements of IEC61000-4-4.
II. Specification of Pego EFT Generator
Model | EFT-5K16SW | EFT-5K30SW | ||
open circuit output voltage | 0.25－5kV ±5% | |||
50Ω load output voltage | 0.125－2.5kV ±5% | |||
Wave sharp of the pulse | 5/50ns into 50Ω/1000Ω loads | |||
Rise time (tr) | 5ns ±30% into 50Ω load | |||
5ns ±30% into 1000Ω load | ||||
Duration (td) | 50ns ±30% into 50Ω load | |||
50ns -15ns to 100 ns into 1000Ω load | ||||
Output Impedance | 50Ω ±20% | |||
Output polarity | Negative, positive, Positive and negative cycling, positive and negative alternating, positive first then negative, first negative then positive | |||
Repetition frequency | 0.1~1200.0kHz ±10% | |||
burst duration | Standard | 15ms@2.5kHz/5kHz,750μs@100kHz,250μs@300kHz | ||
Adjustable | Nos of pulse can be selected at the range of 1 to 255 Burst duration= (pulse number-1)/repetition frequency | |||
Burst period | 100－999ms | |||
Burst mode | Synchronous or asynchronous | |||
Synchronous phase | Free set at 0-3600 , resolution: 1° | |||
Test Procedure | Built in IEC standard test procedure or user-define test procedure (1000 groups) | |||
Built-in coupling and decoupling network (3-phrase and 5 wires) | AC | 3-phase 380V/16A, 50/60Hz | 3 phase 380V/30A,50/60Hz | |
DC | 380V/16A (Max) | 380V/30A (Max) | ||
Coupling mode | L1,L2, L3, N,PE random combination | |||
Coupling capacitor | 33nF ±10% | |||
Environment requirements | Temperature:15°C－35°C; Humidity: 10%－75% | |||
Input | AC220±10%,50/60Hz, 300W | |||
Dimension and weight | 470mm(W)×215mm(H)×500mm(depth) / Approximate 25kg | |||
III. Purpose and Application of EFT Testing
The primary aim of the EFT test is to evaluate the performance of equipment under the influence of EFT. This involves coupling the pulse bursts to the power port, signal port, and control port of the equipment. The key aspects of this test include the rise time, repetitive rate, and low power characteristics of the pulses. EFT testing is applicable to various types of equipment, such as those powered by AC supply networks, those with long DC power cables, and the signal and control ports of equipment. Long AC/DC power cables and signal control cables are susceptible to EFT generated by surrounding equipment, and other devices sharing the same power supply can also introduce EFT that may affect the target device.
IV. Test Targets and Gradesof the Electrical Fast Burst Generator
The targets of the EFT test encompass power ports, signal ports, control ports, and grounding ports. The test aims to establish a common and repeatable standard. According to the IEC61000 – 4 – 4 standard, there are multiple test grades for EFT testing (see Table 1). In the lighting industry, for example, EFT testing is required for lighting devices as per EN61547 Equipment for General Lighting Purpose – EMC immunity requirements clause 5.5. The typical test grades for general lighting devices are shown in Table 2.
Table 1:
Table 2
V. Results of the EFT Pulse Generator
There are four possible outcomes of an EFT test:
A: The equipment operates within the normal performance limits specified by the manufacturer, requestor, or purchaser.
B: The equipment experiences a temporary loss of function or performance degradation that ceases once the disturbance stops, and it automatically recovers its normal performance without the need for operator intervention.
C: The equipment suffers a temporary loss of function or performance degradation that requires operator intervention to correct.
D: The equipment experiences an irreversible loss of function or performance degradation due to hardware or software damage or data loss.
Pego specializes in testing equipment and is dedicated to identifying the most suitable products and providing effective solutions for users. For further information or specific requests, please feel free to contact Pego.
