# AutomationDirect GS21-11P0

Hardware · `GS21-11P0` · verification: source checked

The GS21-11P0 is a DURApulse GS20 series general purpose AC variable frequency drive in an enclosed C-frame housing, mounted on a panel or wall. It takes single-phase 120 VAC input and drives three-phase induction or permanent magnet AC motors with 230 VAC output at 1 hp. It supports SVC, V/Hz, FOC or torque control modes, has integrated dynamic braking, and communicates over RS-485 using Modbus RTU or Modbus ASCII slave.

## Specification

| Property | Value |
|---|---|
| Category | vfd |
| Weight | 1.49685 kg |
| Supply voltage | 120 VAC |
| Rated power | 0.7457 kW |
| Rated current | 4.8 A |
| Frame size | C |
| Output type | PWM output |
| IP rating | IP20 |
| Operating temp min | -20 °C |
| Operating temp max | 50 °C |

## Connected

- Manufacturer: [AutomationDirect](https://machineschema.com/manufacturer/automationdirect.md)
- Protocols: [MODBUS ASCII](https://machineschema.com/protocol/modbus-ascii.md), [MODBUS RTU](https://machineschema.com/protocol/modbus-rtu.md)

## Safety

- Safe Torque Off (STO) is built-in.
- Enclosure rating IP20; temperature rating -20 to +50 deg C.
- A user-supplied external fuse is required.
- UL Listed file # E198015; RoHS status Yes (see CE document); CE declarations available. No UL Recognized, UL Hazardous, or CSA file listed.

## Study notes

- Series GS20; controller type general purpose; enclosed housing, panel or wall mounting.
- Input is 1-phase 120 VAC; output is 3-phase 230 VAC.
- Control modes: SVC, V/Hz, FOC or torque. Reverse capability is built-in.
- Variable torque amperage rating 5.5 A; output frequency range 0.1-599 Hz; carrier frequency range 2-15 kHz.
- Communication: (1) RS-485 (RJ45) and (1) USB B port, up to 115.2k baud, Modbus RTU Slave and Modbus ASCII Slave.
- I/O: 7 discrete inputs (24 VDC, sinking/sourcing), 3 discrete outputs (relay/sinking/sourcing, one Form C SPDT relay), 2 analog inputs (current/voltage, 10-bit and 12-bit), 1 analog output (10-bit).
- Input signal options: 4-20 mA, voltage, potentiometer or pulse train. Analog input ranges 0-20 mA / 4-20 mA and +/-10 VDC; analog output ranges 0-20 mA / 4-20 mA and 0-10 VDC.
- Integrated dynamic braking; no integrated EMI filter; not internally bypassed.
- Optional EtherNet/IP and Modbus TCP card available; EtherNet/IP and Modbus TCP are not built in.
- Programming language: ladder. Connector type: spring clamp terminals. Fuse type: user-supplied external fuse.
- Discrete output load current 3 A/point relay, 50 mA/point discrete.
- Item shipping weight 3.3 lb.

## Sources

1. [DURApulse AC General Purpose Drive: 120 VAC, 1hp with 1-phase input, (VFD) (PN# GS21-11P0) | AutomationDirect](https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/general_purpose_vfds/gs21-11p0) (accessed 2026-10-26)
2. [GS21 11P0 cutsheet](https://cdn.automationdirect.com/static/specs/cutsheet/GS21-11P0_cutsheet.pdf) (accessed 2026-10-26)

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