Volkmann AD-1 Adjustable Frequency Drive Board Panel 20001BBG1M1021 0-600Hz

Volkmann AD-1 Adjustable Frequency Drive Board Panel 20001BBG1M1021 0-600Hz

This is a Volkmann Electronic Drives AD-1 adjustable frequency drive control board panel, part number 20001BBG1M1021, mounted on a large red metal backplane. The assembly includes the main AD-1 drive PCB along with a full complement of relays and Spectrol Reliance precision speed-control potentiometers. It was pulled from a Volkmann 70545AA / 70490AA 30/40 KVA adjustable frequency AC drive system rated 0–600 Hz / 0–667 Hz.

Specifications & What's Included

• Manufacturer: Volkmann Electronic Drives
• Drive Board Model: AD-1
• Drive Board Part Number: 20001BBG1M1021
• Drive Board Serial Number: 1888 (visible on label)
• Parent System: Volkmann 70545AA / 70490AA Adjustable Frequency AC Drive
• Parent System Rating: 30 / 40 KVA, 0–600 Hz / 0–667 Hz
• Relay (Qty 1): Potter & Brumfield R10S-E1-Y2-J1.1K
• Relays (Qty 9): Eagle Signal 17P4C 16007 A120 — AC 120V
• Relay Sub-Board: VED 20C14AA (K1 relay module with terminal block TB4, terminals F/G/H/A/B/C)
• Precision Potentiometers (Qty 4): Spectrol Reliance MOD 534 — labeled Speed 1, Speed 2, Speed 3, Speed 4
• Drive board features fuse positions F1, F3, F4 (inline fuse holders, LINE/MOTOR terminal block TB2)
• Control terminal block TB1: labeled F, STOP, RUN, STOP-TRIP
• On-board adjustments: ACCEL TIMER and CURRENT LIMIT trim potentiometers
• Power devices: A4202 transistors on heat sinks (multiple)
• Test points: TP24, TP25, TP28, TP37, TP38 and others visible on PCB
• Mounting: open red metal panel / backplane (no enclosure)
• Multi-conductor wiring harnesses present and intact

Applications

Adjustable frequency AC drive control panels like this Volkmann AD-1 assembly were used to vary AC motor output frequency — and therefore shaft speed — across a programmable range, in this case 0 to 600 Hz. This enabled precise multi-speed control of AC induction motors without mechanical gear changes. The four Spectrol Reliance precision potentiometers (Speed 1–4) provided discrete speed setpoints, while the relay bank handled switching logic for start, stop, run, and trip functions. Volkmann Electronic Drives produced these variable frequency drive systems primarily for industrial applications requiring tightly controlled AC motor speeds, such as machine tool drives, conveyor systems, and industrial process equipment. This panel dates from the era of discrete-component analog VFD design, before fully digital inverter drives became the industry standard in the late 1980s and 1990s. It is suited for use as a repair/replacement assembly in an existing Volkmann 70545AA or 70490AA drive system, or as a source of serviceable components including the Spectrol Reliance potentiometers and Eagle Signal relays.