PowerFlex 753
With the advent of technology and growing economies, energy consumption is increasing. Electrical energy consists of 20% of the total consumption of energy globally. Of which 50% of electrical energy is used by motors. If we use AC drives with motors to control their speed, about 10% of energy utilization can be reduced to result in a more sustainable life. These AC drives have a very important role to play in society, which includes the production of everyday products. Reducing mechanical stress on power devices and optimizing applications by providing strong control over a process will help with minimizing energy consumption. Even a small speed change in the motor (controlled by the AC drive) creates a huge difference in energy consumption.
PowerFlex 753 AC Drives
The PowerFlex 753 series of AC drives are easy to use, have exceptional performance in industrial applications, and provide flexibility in various operations. Primarily used for general-purpose applications, their power compatibility ranges up to 400 Hp/ 270 kW, and they operate on 24V. This provides tri- slot option for communication, I/O, and safety feedback, which makes it cost-effective. It can deliver a wide range of applications at the user end, reduces transportation costs, and has lower engineering costs. Therefore, it is mostly preferred for assembling machines. It functions with a Safe Torque Off and Safe Speed Motor in applications that demand more safety measures, therefore reducing downtime. The PowerFlex 753 comes in different sizes, which include larger or more compact models that make them space-savvy for applications with low power requirements. It has a Dual-port EtherNet/IP option available as well. It shares a common power structure with which it has the same size and power range.
Parts of a PowerFlex 753 AC Drive
The following are the different parts of a PowerFlex 753 AC Drive:
- LCD Human Interface Module (HIM): Optional support of multi-language
- Option for Multiple types of communication for use in industrial networks available
- 3 digital inputs, 1 relay output, 1 transistor output, 1 analog input, 1 analog output, and 1 PTC input in the form of embedded I/O
- Integral brake resistor
Input Power Wiring
The recommended wiring for PowerFlex 753 drives is to be made of coated copper (75 °C/167 °F). The outer cabinet must be protected from metal chips/ debris when the drill is made.
The signal and the control wiring should not run close to the power wiring because it can cause disturbances in drive operations. To prolong the life of the drive and avoid any damage or destruction, these precautions must be observed.
Output Power Wiring
Shock hazards are caused if the unused wires in the conduit are not grounded which causes the induced voltage. Drives sharing a common conduit must be disabled if even one of them is being serviced or installed so that the possibility of a shock or hazard is nullified. This could otherwise lead to bodily injury. More than 3 sets of motor leads through a conduit can result in electrical noise coupling and any noise reduction method will become ineffective. However, shielded cables are recommended if it is necessary to use three sets of leads in a conduit.
Key Features of PowerFlex 753 AC Drives
Multiple Communication Topologies
The PowerFlex 753 supports an extensive range of network protocols for communication. This helps the user to connect the device easily to any architecture. Other features include multiple network topologies and device-level ring functionality. This is achieved by the option of a dual-port Ethernet/ IP module.
Wide Range of Power Ratings
It has a wide range of power acceptability ranging from 0.75 to 1500 kW (1 to 2000 Hp), plus 400/480 VAC and 600/690 VDC which makes it acceptable for worldwide application.
Enclosures Following Applications Requirements
It also has multiple enclosure options, which can be IP00 open styles or MCC-style cabinets, making them suitable to fit into different space requirements and different safety standards. Different enclosure options follow the application demand. The environmental standards and changes are also met, which adds to its safety and flexibility. The open-type, flange-mountable enclosure is designed for cabinet-mount requirements, whereas the extra protection wall-mountable enclosure is designed to survive harsh environments.
Predictive Diagnostics
The PowerFlex 753 series has multiple protection features which inform the user of any possible maintenance required before time. This reduces unplanned downtime by diagnosing any possible fault. The track of all the previous information is kept in the drive, which prolongs the life of the drive's parts. It has built-in protection devices. They not only calculate the life expectancy of the operating parts based on the factors they are working with, but they also send this information back to the user in real-time. This increases cost-effectiveness, productivity, and performance, therefore reducing the possibility of damage to your investments.
Easy Application Configuration
The PowerFlex 753 series offers the flexibility of slot-based expansion for future applications. Up to 5 option cards can be attached to these AC drives without having to make any unnecessary changes to the hardware. These options include safety, communication, I/O, feedback, and extra 24V DC control power. These can be added up easily whenever required with fewer spare parts.
Automatic Device Configuration (ADC)
Automatic Device Configuration (ADC) is a feature that helps to indicate whether a new PowerFlex device has been inserted into a system. If yes, then the ADC feature helps it automatically download all the configuration that has been made in the application. Not only does this reduce the download time, but also the hassle to make all those changes manually, thus reducing human error. The EtherNet/IP port of the PowerFlex 753 facilitates the ADC feature.
Safety Solutions That Help Improve Productivity
In the past to achieve personal safety, productivity was often compromised, which led to an increase in costs. Now, with PowerFlex 753 AC drives, the configuration of applications is not only achieved efficiently but the safety of the operating personnel is also guaranteed.
Feedback
Many signals are measured and fed back. Options include Universal Encoder and Dual Encoder feedback options. Multiple feedback interfaces ensure the compatibility of wide-ranging applications (such as rotary and linear applications). The feedback loss switchover time is also understood by the drive.
DC Bus Voltage/Memory
If there is a power loss, a comparison value is used to sense it. This is called Bus Memory. If a power loss occurs in the drive, the bus memory helps to recover it via an inertia ride-through or pre-charge option when the power source is reconnected. It is only during deceleration when the bus memory is blocked so that the regenerative condition does not cause a false high value to compare.
Flying Start Feature
When a drive is connected in normal mode to a system where the motor is already spinning at a certain speed/frequency, it can take some time because the drive will usually start at 0 Hz and then match the frequency of the motor. As a result, large currents are generated resulting in an over-current trip. The over-current trip can be very dangerous if the current limiter does not act promptly. This can cause heavy mechanical load/stress on applications while the AC drive tries to synchronize with the speed of the motor.
However, the Flying Start Feature of the PowerFlex 753 series responds vigorously to the ‘Start command’ to match its speed to the frequency, phase, and voltage of the already spinning motor. As a result, the generation of an over-current trip is avoided. The synchronization time between the motor and drive is also considerably reduced. Because of the Flying Start Feature, a very meager or completely zero mechanical stress is laid upon the application.
Analog I/O and Inputs
The PowerFlex 753 drive has a built-in I/O that is expandable according to the increasing demand.
- Two analog inputs per I/O module (up to four I/O modules can be inserted into the drive ports)
- Two analog outputs per I/O module (up to five I/O modules can be inserted into the drive ports)
Digital Inputs
The main control board of PowerFlex 753 AC drives has 3 digital inputs.
- Di 0: Operates on 115 VAC or 24 VDC
- Di 1 and Di 2: Designed for 24 VDC only
Digital Outputs
The main control board has one transistor output, as well as one relay output. Both of these outputs are embedded.
Various Duty Cycles
Different applications have different amounts of overload current applications. PowerFlex 753 drives have two types of duty ratings. ND is the Normal Duty Rating where it can afford 100% continuous current, can take the burden of 110% current for 1 minute, and if the current exceeds 150%, it can survive for 3 seconds only.
The applications requiring high load current in comparison to motor rating, the HD (Heavy Duty) rating, allows 50% extra current for 1 minute and 80% extra current for only 3 seconds.
Options for Attaching Input Devices
The following are the multiple input devices that can be used with PowerFlex 753 AC drives:
- P3 Drive circuit breaker
- P4 drive /Bypass mode circuit breaker
- P6 Drive disconnect switch and fuses
- P7 Drive /bypass mode fused disconnect switch
- P13 Drive circuit breaker
- P14 Drive/ bypass mode circuit breaker
P3 (breakers used for all the ratings are of magnetic thermal type) and P6 (used to disconnect the power supply of the drive) connections are the typical power configuration schemes.
Faults
Any conditions occurring inside or outside the drive that may not be suitable for drive performance are referred to as faults. Faults are significant because they can completely hinder an application. Faults are indicated by an STS indicator, an HIM (Human Interface Module), communication networks, or contact outputs in the form of different colored LEDs.
There are two major types of faults:
- Major/Minor
- Auto Reset Run/Resettable/Non-Resettable/Automatic Drive Reset
Safety Options Available with PowerFlex 753 AC Drives
The following options are available for PowerFlex 753 AC drives to ensure safety.
Passwords
The application configuration and all other settings related to the drive can be protected with the help of a password. With the password set on the host drive, the configurations and parameter settings can be viewed but not changed without an accepted password. The HIM demands a password whenever editing is attempted on a parameter, otherwise, access is denied.
Passwords also help protect the Drive start-up procedure, User sets, Copy-Cat functions, and factory defaults.
Alarms
Any situation that occurs in the drive is indicated to the user with the help of an alarm. These situations can be of any sort that affects the performance of the drive or application. Examples include sudden power loss or the missing of an analog input signal.
A Type 1 alarm is rung for mild situations that do not immediately shut down the drive, but if the situation persists longer, it can cause a fault in the drive. Type 2 alarms are an indication of improper programming, and the drive will not start until the program is corrected, or when the stop function is not assigned to the input with the start function at the same time.
Reactors
Generally, PowerFlex 753 AC drives are directly connected to the correct voltage, However, in that case, the line impedance must be 0.5% or above. This is because a lower line impedance can result in a higher current spike due to a transient voltage spike, resulting in troublesome input, a blown-out fuse, or the frying of the drive’s power structure. For this, an isolation transformer or a line reactor must be added to elevate the line impedance.
Safe Torque Off
Safe Torque Off helps in safely switching off the motor power without having to shut down the drive. Similarly, it allows the system to startup quickly.
Safe Speed Monitor
This allows for easy control and monitoring of the motor speed. It combines the former function with integrated safety relays and safe speed technology, all in one. Maintenance of the operation can be done without stopping the device.
Integrated Safety - Safe Torque Off (STO)
This option provides a hardwired or a networked STO Function through an EtherNet/IP network. With this network, the ‘Safe Torque Off’ command is sent through the GuardLogix controller. The PowerFlex AC drive executes this command.
Integrated Safety Functions
Through this, the PowerFlex 753 series provides Networked STO Function via an EtherNet/IP network, which makes it equipped for Integrated (drive-based) Timed SS1, Monitored SS1, and Safe Brake Control. The Integrated Safety function helps PowerFlex 753 drives communicate with safety I/O.
Bypass
There are two bypass options available for PowerFlex 753 drives.
- B0 No bypass
- B1 Manual bypass
Using a 120V control power source, a motor can be switched manually from drive control to bypass (across the line) operation. Bypass operations have separate contractors from the drive output. However, a backup motor is provided in the bypass mode with an included ‘Bypass’ selector switch.
Ambient Temperature Rating
The PowerFlex 753 series of drives are suitable to operate between the following temperature ranges:
- NEMA/UL Type 1, 12, 4X Enclosure: 0-40 °C (32-104 °F)
- NEMA/UL Type 3R Enclosure: -30-40 °C (86-104 °F)
This temperature range is specific for some intervals when the drive is connected to power, as well as exposed to sunlight. Temperatures outside this range can be harmful to the drive.
Maintenance
The variable speed drive system calls for regular inspection. The inspection intervals should be based on the environmental conditions and the operation intensity, and adjustments should be made accordingly. The cooling system and air regulators should also be frequently checked and replaced if required. The air regulation should be monitored, and the air filters should be cleaned or replaced if the airflow reduces by 10% or more.
