High-performance variable frequency drives (VFD) enable speed control for three-phase AC motors such as those in conveyors, fans, pumps, compressors, HVAC and material handling. High-performance AC inverters in sizes up to 300hp offer advanced features such as Safe Torque Off and a built-in logic controller. A full line of accessories is available to ensure a reliable installation.
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The DURApulse GS4 series of AC drives includes many of the same standard features as our other GS drives including dynamic braking, PID, removable keypad, and much more:
GS4 Series drives start at
A fully functional PLC is built in to the GS4 drive. Capable of up to 10k steps for drive related logic requirements. Control the drive and I/O including full PID functions with standard ladder logic and free downloadable GS Logic PLC software. Advanced PLC features include real-time calendar/clock and full PID control.
Built-in I/O includes eight DC digital inputs, two DC digital outputs (up to 48V), and five analog channels (3 inputs and 2 outputs) configurable for either voltage, current or potentiometer (input). The expansion I/O slot accepts any one of the three I/O option cards (DC In/Out, Relay Out, AC Input).
GS4 drives support both Modbus RTU and BACnet (serial) protocols as standard. GS4 drives also accept an optional Modbus TCP or EtherNet/IP Ethernet card for fast network access at low cost.
The LCD keypad on the GS4 is text-based with full English parameter names/descriptions (The keypad also has the ability to switch to Spanish and French) and can configure and store up to 4 complete sets of drive parameters for backup and recovery operations. Beyond initial drive setup, the keypad can be used for run/stop control of the motor and as a scalable speed or frequency display. The keypad can be configured to scale and display relevant units for the application (GPM, FPM, etc). The keypad can be remotely mounted with a simple bezel kit with a standard Ethernet patch cable and has a NEMA1 rating with IP20 ingress protection.
The embedded Quick Start menu has the most common motor parameters listed together and values referenced from the motor nameplate are entered for faster drive start-up.
GS4 drives have the ability to upgrade the drive, the firmware in the intelligent keypad, and the optional Ethernet card. A standard USB cable is connected to the drive module to download the latest firmware.
The GS4 drive can control up to 8 motors in parallel, cyclic or cascading fashion by using a combination of VFD control, relay outputs and across-the-line control. Relay outputs on the drive control contactors that allow the VFD to control one or more motors while additional relay outputs provide across-the-line control of other motors via a separate contactor.
The GS4 drive offers five different control modes for circulation pump control.
GS4 Drives support full Proportional, Integral, Derivative (PID) control to bring complex processes up to speed, pressure, force, feed rate, flow rate, position, etc. with little or no overshoot.
GS4 drives are designed for long-life, and maintainability, w/self-diagnosis for key components. The modular design promotes quick expansion and easier maintenance. Internal circuit boards all have conformal coating to protect against moisture, dust, chemicals, and temperature extremes.
A 100kA Short Circuit Current Rating (SCCR) is required for personnel safety in many factory environments and to meet a host of regulatory requirements. SCCR is defined as the maximum short circuit current a component, or assembly can safely withstand when protected by a specific overcurrent protective device, or for a specified time interval.
The heatsink design of the GS4 provides a 50°C rating allowing the GS4 to operate in harsh ambient conditions. All the GS4 drives up to 215 HP can be "flange mounted" with heatsinks on the outside of the enclosure allowing the use of a smaller enclosure or reducing the need for enclosure cooling.
The Safe Torque Off (STO) function is a basic drive-integrated safety feature. Use this input signal to ensure that no torque-generating energy can flow to the motor. Often used in emergency stop situations and/or to prevent unintentional motor starting. STO saves money by eliminating the need for a large contactor that drops power to the drive when the safety circuit is disengaged.
The GS4 fire mode is used as a last resort in emergencies and certain situations to have uninterrupted smoke removal and system pressure. The drive will ignore certain alarm inputs and reset immediately on any trips.
While all GS4 Drives are capable of dynamic braking, the smaller sized drives below 40 hp have the capability built-in. The larger drives (above 40hp) require an optional Dynamic Braking Unit. A comprehensive line of braking units, thermal overloads, and braking resistors is available.
A DC choke is used to reduce the effects of harmonics in VFD applications. Larger GS4 drives (above 40hp) have the DC Choke built-in; smaller GS4 drives can use an optional DC choke.
This "flying start" or "catch on the fly" control technique allows the GS4 to take control of a motor that is already spinning. The GS4 drives can send small current signals to the motor to detect the motor's speed, and then engage the motor in full V/Hz or sensorless vector mode within a few seconds. This eliminates potential large inrushes of current when applying power to an already spinning motor.
A standard temperature sensor signal (such as an RTD) from a motor can be wired into the GS4 drive to protect the motor from overheating. RTDs or PTC thermistors can be used, and it is a UL requirement in some applications.
All GS4 drives can be panel (wall) mounted. GS4 drives up to 215 HP can also be "flange mounted"; a thru-mounting technique that puts the drive's heatsinks on the outside of the enclosure. The smaller A through C frame size drives have optional flange mount kits; D through F frame sizes come with flanges already attached.
Optional conduit boxes allow larger GS4 drives to be mounted without an enclosure in many applications - saving considerable cost and installation time. GS4 drives with conduit boxes are rated for IP20, UL Type 1, and NEMA1.