The development prospect of frequency conversion technology

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With the explosive development of modern industry, global energy demand is increasing. Non renewable energy is drying up. Energy saving and consumption reduction is a common problem faced by all countries at this stage. With the development of frequency conversion technology is becoming more and more mature, widely used in all walks of life using energy-saving inverter technology, compared with the traditional fixed frequency control, frequency conversion control mode of low energy consumption, simple operation, easy maintenance, creating conditions for engine cooling with variable frequency energy saving scheme, to open the market.

In the past, the ship's cooling water pump and the engine room fan were all fully loaded at full speed according to the design, but in fact, many ships Often run at lower cruising speed, so the system running in the light load state resulting in water pump, valve, fan and wasted a lot of energy. In recent years, many cases show that the transformation through the installation of frequency conversion on the cooling water pump control system can realize the power saving of 50~80%.

Renergy low THD sea water pump VFD control system

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1.Product overview

2. Control system

There is a master switch system in the control cabinet to control three pumps, each of which has three state positions.

Manual stop automatic mode

1# and 2# inverter can be used as the main driver of the system. There are 2 temperature sensors in the system. They are connected to 1# and 2# drivers to meet the redundancy control requirements. The main driver will maintain a constant LT temperature, and control all the pump speeds by master slave cascade. All the pumps in the work run at the same speed, and the system turns three pumps to balance their running time. Renergy provides a complete set of system configuration and installation and debugging.

3. Low THD sea water pump VFD control product standard parameters.

 Standard Table                  380V-480V    50/60HZ    Air  cooled     IP44

Item	Pump motor  capability（kw）	Type	Dimension (mm)			Weight （kg）	Rules
			W	H	D
1	30	RE-ESS30	1800	2000	600	450	ALL
2	55	RE-ESS55	2100	2000	600	520	ALL
3	75	RE-ESS75	2200	2000	600	710	ALL
4	90	RE-ESS90	2200	2000	600	710	ALL
5	120	RE-ESS120	2500	2000	800	100	ALL
6	160	RE-ESS160	2500	2000	800	1150	ALL

4. Product advantages
>  energy saving, adopting frequency conversion control method, compared with traditional fixed frequency method to save 40% of the system, reduce greenhouse gas emission;
>  is simple to operate and easy to maintain;
>  is easy to transform, with short transformation time, low input cost and high rate of return.
>  startup current is low, effective protection pump life;
>  harmonic design, the whole system is reduced within 5% at run time, preventing damage to other equipment on the power grid;
>  safe and reliable, redundancy design, USES the amphibious a prepared plan, prevent in the case of a frequency converter fault, in a timely manner to enable the standby pump operation, ensure the satisfaction of the cooling water flow rate, according to the requirements of water temperature and the working condition of the host used timely and automatically adjust the number of running pumps, to achieve energy saving purpose;

>  Bypass Bypass is used to increase the Bypass selection of the frequency converter, so as to prevent the frequency converter from being damaged, Bypass the frequency converter to run the system and ensure the continuous and reliable operation of the system;

Case analysis:
Design temperature: 32 ℃
The actual temperature: 20 ℃
Run hours (per year) : 6000.
Electric power cost per KW/h: €0.1.
Unoptimized system energy consumption: 75KW=450.000KWh/ year.
Optimized system energy consumption: 14KW=84.000KWh/ year.
Energy saving: 80%
Annual cost savings: €36,000.
Installation of variable frequency system cost:  € 32,000.
Investment recovery time: less than 12 months.

Payback amount for 2 year operation with installed

Motor(kW)           =No. Of operating Pump*Pump(kW)

Motor(HP)           =Motor(kW) / 0.746(kW/HP)

Fuel Consumption(kg/hr)  =Fuel Consumption(kg/HP*hr)*Motor(HP)

Fuel Consumption(US$/hr)  =Fuel Consumption(kg/hr)*Fuel Cost(US$/kg)

Daily Cost for Fuel(US$/day)=Fuel Cost(US＄/hr)*24hr

Annual Cost for Fuel(US$/year)=Daily Fuel Cost (US＄/day)*Operating Day(day)

Annual Saving Cost(US$) =Annual Fuel Cost without ESS(US$)-Annual Fuel Cost with ESS(US$)

RE-S series motor control cabinet can be star-delta-starting, soft starting, Auto-trans transformer starting,and frequency converter starting our cabinet have function on high protection for motors,the cabinet have all necessary alarms and in-time monitor controls, With features on high protection for motors, offers varieties alarms and in-time monitor controls,It makes motor and drives systems more reliability, safety and stability.

Product of application:

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RE-S series motor control cabinet can be widely used in various power range bow thruster application. It control three-phase AC motor starting and protect the motor, It also applies for varied application of marine special equipment motor, big capacity pump motor, large crane motor and others. To remotely control motor starting, stopping and speed regulating.

Product Features: 

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> The motor overload protection and short circuit protection, and maximum protection of the motor > Local control and remote control, convenient the commissioning and operation

> Having a key auxiliary start function to simplify the start up process > Hardware and software double emergency stop interlock, a significantly improve the safety

> Original starting mechanism security to prevent the miss operation > Providing heating and ventilation device to adapt to the ship special environment

Propulsion Remote control      Azimuth Propulsion      Bow thruster Control      Main propulsion Control

There is a growing trend in the market for electrical propulsion concepts. VFD propulsion systems offer advantages for ships with following special requirements.

> Low noise and vibration.
> Space saving aspects.
> Economic operation.
> Higher reliability, availability and redundancy.
> Flexible use of the torque-speed characteristic.
> Excellent dynamic characteristic.
> No interference of the main.
> Reduced emissions.
> High automatically.
> Reduced wear and fatigue damage.
> Depending on the requirement of ship redundancy and operation line, synchronous frequency converter or PWM inverter is used to drive synchronous motor or asynchronous motor, which can be proved to be a very reliable propulsion solutions.

Frequency Controlled Drive Systems

Frequency inverters  have become an important element in the field of drive systems enabling configurations with stepless speed control from zero rotations up to the rated speed.In the field of drive motor control systems RRR Electronics provides solutions with integrated frequency converters especially designed for sophisticated pump systems such as cargo pumps, ballast pumps, jet and gland-water pumps as well as similar applications.

Modern, highly developed pump systems call for the need to maintain the highest possible discharge or flow rate while keeping all system conditions such as the pressure values on the suction and discharge side of the pump within the permitted limits.Other systems demand a continuos supervision of the actual flow rate or the mechanical and thermal strain (i.e.vibrations, cavitation, structure born noise).

Integrated control function

An integrated Programmable Logic Computer (PLC) observes the relevant system conditions such as the pressure values on the suction side of the pump and controls the drive motor speed according to the programmed limits.

The software of the PLC is specially designed for the different requirements within the ship’s system and the relevant pumps. An automatic control mode which will keep the discharge or flow rate at the highest possible level while preventing dangerous cavitation can be provided and will be adapted for the different demands on site.

The following advantages can be obtained for all application of variable frequency drive control pump speed:

> Optimum speeds for any hauling condition within the cargo system can be automatically or manually adjusted. > Automatic and reliable protection against operation of the equipment outside the ermitted values (no cavitation, no over pressure, no over temperature, etc.) > High adaptability for many different unloading sites and hauling conditions as well as for different viscosity of the cargo.

> Automatic supervision and monitoring of all relevant system conditions (pressure, flow rate, temperature, vibration, etc.) > Soft starting and step less change of speed leading to less wear and stress of the materials, thus enlarging life time and reliability > Pumps will start and run up with rated current only.

Crane ship     Dredgers ship

The frequency converter drive  is the best solution for a stepless control. It finds its application in the wide spectrum of winch and crane drives.

The advantages of inverter driving stepless control:

> Low maintenance requirements 

> Low starting currents

> Precise control

> Smooth operation

> Less wear of ropes and on mechanical parts

> Low noise radiation

Renergy has created a world-class research and development team, solar, wind, Marine energy, nuclear power, renewable energy products such as natural gas, which have been successful in some pilot tests. As the same time, Renergy products can reduce the emission of carbon dioxide electricity use. 

Main features of shore power supply:

> Efficient environmental protection, green energy saving.

> Safe and reliable, easy to maintain. 

> Stable frequency voltage and adjustable.

> Low harmonic distortion low THD < 2%.

> Low noise and no pollution.

Energy storage technology will provide the following advantages:

> Reduce fuel consumption.

> Improve vessel performance.

> Reduce engine running time.

> Increase redundancy.

> Reduce NOx, SOx, and CO2.

> Improve diesel engine efficiency.

> Improve  working environment.

Italy marelli has a variety of motor types, designed for ship application.

Mounting
Vertical or horizontal feet and/ or flange mountings.

Cooling

Marelli Marine motor cooling methods include:

> TEWAC-Totally Enclosed Water to Air Cooled          Type：A series of B4V

> ODP-Open Drip Proof                                             Type：A series of C3M-C4M-C3W-C4W

> TEWC-Totally Enclosed Water Cooled                     Type：A series of B4J-B5J

> TEFC-Totally Enclosed Fan Cooled                          Type：A series of B5M-A5M

Approval
Marelli motors are designed and built in accordance with marine register rules specifications and comply with: ABS, BV, CCS, DNV, GL, KR, LR, NK, RINA, RS and others.

General features
Marelli Motors are robust machines designed for continuous duty in tough marine environments. We offer a wide range of asynchronous motors, for high torque/low speed or special demand for high efficiency and when low weight is required.
> Protection degree, IP23 - IP44 - IP55.
> Poles, 4-6-8-10 
> Anti-friction bearings or sleeve bearings
> Anti-condensation heaters
> PT100 sensors for sleeve bearings
> PT100 sensors for windings
> Vacuum pressure insulation (VPI) and tropicalization winding system
> High quality insulation for inverter supply applications
> High quality encoders or resolvers for speed/position feedback to inverters
> Voltage 400V - 50Hz, 450V - 60Hz, 690V - 50Hz and 60Hz, or special voltage and frequency optimized to specific applications.

> The motor is suitable for a variety of occasions，such as：Propulsion、Thrusters、Dredge pump、Winch、Cargo oil pump、Sea water pump

Marelli generators are designed to offer not only the best possible reliability, but also the best technical solution.

Cooling

Marelli Marine generators cooling methods include:

> TEWAC-Totally Enclosed Water to Air Cooled           Type：A series of MJHRM/MJRM

> ODP-Open Drip Proof                                              Type：A series of MJHM/MJBM

> TEAAC-Totally Enclosed Air to Air Cooled                 Type：A series of MJVM

Reliability
> Long life endurance of electrical components and housing
> Generators are impregnated with high-grade resin by a VPI process and an additional protection against hostile environmental conditions (tropicalization) is provided as standard
> Large security factors to ensure reliability for the work operating conditions

Performance
Active parts are designed by using the latest technologies and the best materials available to guarantee high efficiency values.

Approvals
The generators are design and built in accordance with marine register rules specifications and comply with: ABS, BV, CCS, DNV, GL, KR, LR, NK, RINA, RS.

Safety
> Leackage detector for water cooled generators (IC81W/IC86W solutions)
> CT`s for differential protection (above 1500kVA)
> Interface towards external safety systems like B.O.S.S. for rapid action in case of failure situations
> PT 100 sensors for temperature monitoring of stator winding and bearings.
> Anti-condensation heaters are available for all frame sizes.

Totally customisable
> Prepared for vibration sensors
> Anti friction or sleeve bearings are available. For sleeve bearings, forced lubrication and jacking system are available for special or low speed applications 
> Hybrid propulsion possibility using special exciter system for nominal torque from low speed
> Digital excitation/AVR systems acc to customer requests
> Degree of protection from IP23 to IP55
> 50Hz/60Hz or variable speed solution for DC grid solutions
> Speeds/Poles not mentioned in the brochure are available on request. 
> Nominal voltage from 380 to 6.600 Volts
> All generators are customizable to for optimal performance for each specific project