# AutomationDirect GS4-21P0

Hardware · `GS4-21P0` · verification: source checked

The GS4-21P0 is a DURApulse GS4 series AC high-performance variable frequency drive in a NEMA 1 enclosure. It operates from 230 VAC with either 3-phase or 1-phase input and provides 1 hp or 1/2 hp respectively. It supports SVC or V/Hz control, has an RS-485 port, and includes integrated dynamic braking.

## Specification

| Property | Value |
|---|---|
| Category | vfd |
| Supply voltage | 230 VAC |
| Frame size | A |
| Output type | PWM output |
| IP rating | IP20 |
| Operating temp min | -10 °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

- Built-in Safe Torque Off (STO) function.
- UL Listed, file E198015.
- CE marked and RoHS compliant; EU REACH documentation available.
- Rated ambient temperature range: -10 to +50 °C.
- External fuse is user-supplied.

## Study notes

- Input phases: 3 and 1; output phases: 3.
- Horsepower: 1 hp with 3-phase input, 1/2 hp with 1-phase input.
- Amperage: 4.8 A with 3-phase input, 2.4 A with 1-phase input; variable torque rating 5 A.
- Control modes: SVC or V/Hz.
- RS-485 (RJ12) port supports Modbus RTU, Modbus ASCII, and BACnet at up to 115.2k baud.
- Optional EtherNet/IP and Modbus TCP cards are available.
- Input signal: 4–20 mA, voltage, or potentiometer input.
- Output frequency range: 0.1–599 Hz; carrier frequency range: 2–15 kHz.
- 8 discrete inputs (24 VDC, sinking/sourcing); 4 discrete outputs (relay/sinking/sourcing).
- 3 analog inputs (11-bit) and 2 analog outputs (10-bit).
- Integrated dynamic braking and built-in reverse capability.
- For use with 3-phase induction motors; programming language: ladder; screw terminals.

## Sources

1. [DURApulse AC High-performance Drive: 230 VAC, 1hp with 3-phase input, 1/2hp with 1-phase input, (VFD) (PN# GS4-21P0) | AutomationDirect](https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/high-performance_vfds/gs4-21p0) (accessed 2026-10-26)
2. [GS4 21P0 cutsheet](https://cdn.automationdirect.com/static/specs/cutsheet/GS4-21P0_cutsheet.pdf) (accessed 2026-10-26)

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