Technical(FAQ) After sale service Warranty

Frequency Converter

Click: 2521  Date: 11/1/2017 10:01:34 PM

 Frequency Converter FAQ


Question : Can it ok to add an RS232 OR RS485 Port on the frequency converter and does it can support RS232 and RS485 together


Yes, it is ok , can add RS232 OR RS485 Port on the frequency converter for communication

But we did not offer the software but only the protocol Content

In addition , it only can choose RS232 or RS485 and can not make RS232 and RS485 in a one frequency converter




Question3: Can we customize 220VAC Input/output 3 phase frequency converter?



 we can.




Question : Does our frequency converter can make 400HZ output? If yes,which fields it can be applied to?


Yes, we can make 400HZ output frequency converter

It can be applied to aircraft ,military and so on




Question : Can the input and output voltage/ phase be different?


Yes, it can be different.

For example:

If the input voltage is single 220VAC, The output voltage can be single phase 220VAC , also 3  

l  phase 380VAC is OK.


Question 6: What is the technology Features of frequency converter?


Adopt separate (standalone), no power transformer structure, input non-isolation, output isolation

High precision true effective value digital meter display: frequency, voltage, current, active power, power factor, high precision and strong anti-interference ability

The transient response speed ,100% loading / unloading, the reaction time within 2ms.

The output frequency: 50Hz, 60Hz, 4763Hz400Hz, load frequency stability + 0.1%.

output voltage : phase voltage 0 ~ 300V (line voltage 0 ~ 520) can be simulate all voltages of the world, load voltage accuracy: + / - 0.5% (resist load). Phase difference: 120°±2°

The constant current design, can easily start the motor with high starting current load.

With overvoltage, over current overload and over temperature of multiple protection and alarm function.




Question 7: For the output frequency / voltage / current / power , how many digit display?


4 digit display for voltage / current / power

3 digit display for frequency


Question 9: What is the working principle of frequency converter?


Frequency converter is to make the alternative current of electric supply through transfer process of ACDCAC

Pure sine wave output

The output frequency and voltage can be adjusted within a certain range


Question : What is application field of frequency converter ?


 Home Electrical Appliances industry. Such as: air conditioning equipment, washing machine, microwave oven, included sound machine, refrigerator, DVD, scrubber, electric razor products for testing power and so on

 motor, electronic industry. Such as:transformer, electronic stabilizer, AC fan, UPS system, charger, relay, compressor, motor, passive components and other products and so on.

IT industry and computer equipment. Such as: fax machine, copy machine, paper shredder, printers, scanners, burner, servers, monitors and so on..

The laboratory and test unit. Such as: AC power supply testing, product life and safety testing, electromagnetic compatibility testing, OQC (FQC) testing, product testing & research and so on

Aviation / military units. Such as: airport ground facilities, ships, aircraft, military and so on.




Question  how to calculate high and low frequency power output current


Method 1:

In the industry, if the frequency converter use all-copper transformer and enough power, work on the lower voltage , the rate voltage is 120VAC, work on the higher voltage , the rate voltage is 240VAC,

For example , single phase output 3KVA converter ,

The max current output is 3000/120= 25A, It is about 25a when work on the lower rate voltage is 110VAC

The max current output is 3000/240= 12.5A, It is about 12.5a when work on the higher rate voltage is 220VAC

Method 2:

Single phase output:  

1. Low-grade Current=4.5A*Capacity

2. High-grade Current= low-grade Current=4.5A*Capacity*2

Three phases output: 

1. Low-grade Current= Phase capacity/120V

2. High-grade Current= Phase capacity/240V

Notice: we will use the rounding-off method to decide the final amount.




Example:  Three phases output YK-BP8830 frequency converter:

1.   Low-grade Current= Phase capacity/120V=10000/120=83.33=84A 

2.   High-grade Current= Phase capacity/240V=10000/240=41.66A=42A




Question: can you customize 19 inch rack mount type frequency converter?


l  Yes,

l  All of the model less than 2KVA can be customize as 19 inch rack mount type.


Question: If you purchased 50-60hz power back, but you found the frequency range is not wide enough, can not meet the load operation, you can replace your own internal parts to change the frequency range ?



 But you have to follow the change step that engineer given strictly, or if there are any problem can lead the power supply damage.


Question:  If the end user only know the max output current work in one voltage , how to select the right model converter


Method 1

1.       confirm what kind of load will connect with the converter

2.       If the Sensibility load, then select the frequency converter must be three times the rated power

3.       Confirm the current work in how many voltage ?

4.       Base on the rate max output current on our specification to choose the right one

For example

If the end user request 90VAC Output at 10A ,  the load is air conditioner

Air conditioner is the Sensibility load

2KVA Converter . max current output is 16.8A When work in 0-150vac

1KVA Converter . max current output is 8.4A When work in 0-150vac , can not meet demand

So select 2*3=6KVA frequency converter

Method 2

Resistive: power capacity = 1.1 * load power

Sensibility: power capacity = load starting current / load rated current * Load power

Rectification: power capacity = load current wave crest factor /1.5* load power

Mixed: Please choose an appropriate proportion according to different load


(Note: For inductive load refrigerators, air conditioners and the other sensitive load, we should select the frequency converter base on the starting power supply capacity.)


Question what is the phase voltage and line voltage


Phase voltage only own for the 3 phase output power supply

Phase voltage = any wire line voltage + Nero line voltage

Line voltage = 3 line of wire cable voltage


Question   what is different between line frequency converter and IGBT Frequency converter



line frequency converter

 IGBT Frequency converter

Circuit mode

Transistor amplifier


Waveform distortion


2 %

Reaction time




Question:  the output of frequency converter can be adjust from 0hz example 0-500Hz adjustable ?


1.       No , it did not support

2.       The lower frequency is 35hz -500hz


Question  : Does the frequency converter can make 0-1000VAC output


Yes, it can

For example , 3 phase input and output 30KVA 0-1000vac output frequency Converter

When work in lower grade , the phase voltage is 0-288vac m line voltage is 0-500vac, the max current is 20A

When work in Higher grade , the phase voltage is 0-580vac m line voltage is 0-1000vac, the max current is 10A


Question, How to define frequency converter input and output specification can make 3 phase 4line , 3 phase 5line , 3 phase 3line ?


3 phase 3line – 3* wire cable

3 phase 4line--3* wire cable+ 1* Nero cable

3 phase 5line ---3* wire cable+ 1* Nero cable+1*Ground cable


Question  Does the frequency converter with the memory function for preset value?



After save the presets value , you can check the presets value again when you restart the converter


Question ; For the YK-BP81 series frequency converter with 400hz output option , does it can work in 24*7 hours?



It did not work in a long time , but it can work 5-30min every time , if you did not stop it after 5-30mins , the converter will be broken .

 If you need 400hz output design and work in all the time , please contact with our company for quotation


Question: what is the efficiency of YUCOO frequency converter ?


 Efficiency  80%




Question: Does the YUCOO frequency converter can be programmed?


 Yes. But there only the YK-BP80 Series, YK-BP8101 1kva & YK-BP8102 2kva two models.

  YK-BP80 Series Frequency Power Description:

1.         High-precision frequency stabilization, rapid adjustment button voltage, frequency, output voltage programmable dynamic

2.         Precision True RMS digital meter display: frequency, voltage, current, active power

3.         Unique output voltage frequency group shortcuts, can be set 5 group frequency, voltage, and run time (optional), convenient

4.         Output frequency: 45 ~ 70Hz (400Hz optional), load frequency stability of ± 0.01%.

5.         Output voltage: 0 ~ 300V adjustable (can be customized to 1000V), can simulate the world voltage, load regulation accuracy of ± 0.5% (resistive load)

6.         With RS-232 interface (optional)

7.         The transient response speed, 100% load / to set the regulator within 2ms response time

8.         With over voltage, over current, overload, over temperature protection and alarm functions such as multiple

9.         The main components are the use of imported, reliable quality




Question: What is different between Frequency converter and AC Driver?


  Frequency Converter is the AC mains through the AC - DC - AC conversion, pure sine wave output, the output frequency and voltage adjustable within a certain range.

 Ideal AC power supply features a frequency stability, voltage stability, resistance is zero, the voltage waveform is pure sine wave (no distortion). Variable frequency AC power supply is very close to the ideal.

 AC Drives is the application of inverter technology and microelectronics technology, by changing the frequency of the motor operating power to control AC motor power control equipment.


Question: How to choose the right model of frequency converter YUCOO Manufacture?


1.       Please check below table and find the different service in different specification

2.       For 3 phase output , it should be choose YK-BP83 Series

3.       For 400hz output , should be choose YK-BP88 Series, as YK-BP80 Series and YK-BP81 Series 400hz output did not support long time operating

4.       If the frequency converter should be working in vessel, please let us know before purchase

5.       If you can not choose the right one, please tell us detail for your application then we can recommend the right model for you


Input voltage

Output voltage

AC Input frequency

AC output Phase voltage

Output frequency

Output capacity

Output adjust type

YK-BP81 Series

1phase/3 phase

1 phase




50/60hz, 45-70hz, 400hz option


Knob type

YK-BP80 Series

1phase/3 phase

1 phase





220v/50hz, 110v/60hz, 120v/60hz


Press key type

YK-BP83 Series

1phase/3 phase

3 phase




50/60hz, 45-70hz, 400hz option


Knob type

YK-BP88 Series

1phase/3 phase

1phase/3 phase




400hz for military or aircraft


Knob type