Allen‑Bradley 1336‑PRE‑VB078‑AA Power Module Product Description

Overview

Allen‑Bradley 1336‑PRE‑VB078‑AA is a power section module for the Allen‑Bradley 1336 PLUSⅡ series variable frequency drive. This AB power module includes rectifier bridge, IGBT inverter stack, current sampling circuit and heat sink assembly, which must be matched with the 1336 control board to form a complete drive. 1336‑PRE‑VB078‑AA corresponds to 78 A output rating, used for three‑phase AC motor speed regulation. It is an obsolete legacy component, commonly used for production line maintenance and spare‑part replacement of existing 1336 PLUSⅡ drive systems.

Features

Allen‑Bradley 1336‑PRE‑VB078‑AA power module integrates diode rectifier and IGBT power switching devices for AC‑DC‑AC conversion. This AB power module carries built‑in current transformers for overcurrent detection and temperature sensors for IGBT thermal protection. 1336‑PRE‑VB078‑AA receives PWM drive signals from the control board and feeds current and temperature feedback signals back for closed‑loop protection. The AB power module adopts forced air cooling structure and supports heavy intermittent load operation. This power module supports V/F control and vector control when paired with the matching 1336 control board.

Specs

Allen‑Bradley 1336‑PRE‑VB078‑AA power module

• Brand: Allen‑Bradley (Rockwell Automation)

• Series: 1336 PLUSⅡ

• Model: 1336‑PRE‑VB078‑AA

• Rated output current: 78 A

• Voltage class: 400V class

• Cooling: Forced air cooling

• Internal components: Rectifier, IGBT inverter, CTs, temperature sensor

• Matching control board: 1336 series control PCB

• Status: End of life, legacy spare

Principle

Allen‑Bradley 1336‑PRE‑VB078‑AA power module converts incoming three‑phase AC into DC voltage via the rectifier stage. The control board sends PWM signals to drive the IGBT bridge, generating variable‑frequency, variable‑voltage three‑phase AC to drive the induction motor. Sampled current and temperature signals are transmitted back to the control board. When overcurrent, short‑circuit or overheat is detected, the control board blocks PWM pulses and triggers fault alarm to protect power devices.

Applications

Allen‑Bradley 1336‑PRE‑VB078‑AA power module is widely deployed in fans, pumps, conveyors, textile machinery and processing equipment equipped with 1336 PLUSⅡ drives. This AB power module serves as the power core for variable speed energy saving and motor regulation. 1336‑PRE‑VB078‑AA fits spare replacement on legacy Rockwell 1336 drive cabinets.

Installation & Maintenance Notes

Follow official Allen‑Bradley 1336 service manuals during installation of 1336‑PRE‑VB078‑AA power module. Strictly confirm DC bus discharge before opening the unit. Check power terminal torque, cooling fan and heat sink cleanliness regularly in dusty environments. Back up drive parameters before power module replacement. Confirm exact part number 1336‑PRE‑VB078‑AA before spare‑part swap‑out to verify current rating, voltage class and control interface compatibility.