A variety of safety precautions are built into the PowerFlex 755 AC Drive’s design to help safeguard persons working with or near the drive as well as the drive itself and the equipment it controls. Here are a few of the PowerFlex 755 AC Drive’s safety features:
1. Safe Torque-Off (STO):
When the drive is stopped, this function reduces the motor’s torque, preventing the motor and the equipment it controls from moving unexpectedly.
The drive’s output is turned off and the motor’s torque is reduced when STO is engaged. As a result, the motor is guaranteed to remain stationary until the STO function is reset. STO can assist avoid damage to the machinery that the motor is controlling in addition to shielding people from the movement of the motor.
The drive is normally instructed to shut off the output and reduce torque from the motor when the STO function is triggered by a switch or other device. While some STO devices may be attached outside to the drive, others may be included into the drive itself.
Read: Rockwell Automation 20G11NC015JA0NNNNN 755 AC Packaged Drive
2. Safe Speed Monitor (SSM):
This function keeps track of the drive’s output speed and evaluates it against a set safe speed limit. The drive will shut down to prevent unsafe operation if the speed limit is exceeded.
In cases where the motor speed needs to be carefully controlled for safety, the SSM function can be especially helpful. The SSM function, for instance, can be used to control how quickly a conveyor belt or other piece of moving equipment moves when a motor is driving it, which could endanger the safety of workers nearby.
The user must first select a motor speed limit that is safe before using the SSM feature. This restriction is usually based on the demands of the application and is intended to guarantee the motor’s and the equipment it controls’ safe operation. The SSM function constantly checks the motor’s speed and compares it to the safe speed limit after the safe speed limit has been set. The drive will stop off and a notification will appear if the motor speed exceeds the safe speed limit.
3. Safe Stop 1 (SS1):
When a problem or emergency stop is identified, this feature allows for a controlled deceleration of the motor to a safe stop.
The drive uses a controlled ramp down in motor speed to slow the motor to a safe stop when SS1 is engaged. This lessens the likelihood of abrupt halts or jerky motions that could endanger people or property. The SS1 feature not only ensures a secure stop, but it can also help the engine and equipment last longer by minimising wear and tear brought on by abrupt stops.
A switch or other mechanism that instructs the drive to begin the controlled deceleration normally activates the SS1 function. Some SS1 devices might be built inside the drive itself, while others might be attached externally to the drive.
4. Safe Stop 2 (SS2):
Another security feature of the Allen Bradley PowerFlex 755 AC Drive is Safe Stop 2 (SS2). By keeping an eye on the drive’s output and ensuring that the motor stops safely in the case of a problem or emergency stop, the SS2 function adds an extra layer of protection.
When SS2 is engaged, the drive monitors the output and, in the event that a fault or emergency stop is identified, starts a controlled deceleration of the motor to a safe stop. This aids in preventing sudden stops or movements of the machinery the motor is in charge of, which could endanger people and property. The SS2 feature can also aid in preventing damage from unexpected stops to the motor and other machinery.
5. Motor overload protection:
Another safety feature of the PowerFlex 755 AC Drive is motor overload prevention. This function is intended to safeguard the motor against harm brought on by high heat buildup as a result of overloading or other problems. The insulation, windings, and bearings of the motor may be harmed by an excessive current flow and overheating that results from overloading.
The PowerFlex 755 AC Drive has a number of motor overload protection mechanisms to guard against damage to the motor from overloading. Among these is thermal overload protection, which keeps track of the motor’s temperature and lowers the drive’s power if the temperature rises above a safe level. Additionally, the drive has current overload protection, which tracks the motor’s current consumption and lowers the drive’s output if the current goes above a safe threshold.
6. Ground fault protection:
Another safety element of the PowerFlex 755 AC Drive is ground fault prevention. When an electrical current travels from an energized conductor to the ground or another conductive surface, a ground fault is created. Numerous things, including deteriorated insulation, dampness, or contact with a conductor, can result in ground faults. Because they can result in fires, equipment damage, or even electrical shock, ground faults can be hazardous.
To assist prevent these risks, the PowerFlex 755 AC Drive has ground fault protection. The ground fault protection circuitry of the drive keeps track of the current moving through its ground channel and cuts off power to the drive if a ground fault is found. This lessens the chance of an electrical shock and equipment damage brought on by a ground fault.
7. Short circuit protection:
In the case of a short circuit, the drive has short circuit protection to assist avoid harm to both the drive and the equipment it controls.
8. Overvoltage/Undervoltage protection:
The drive keeps track of the input voltage and will turn off if it goes above or below a set range, helping to safeguard the drive and other equipment from harm.
