1. General Information

• Part Number: 528061, 0-52806-01, 0528061

• Manufacturer: Reliance Electric (later ABB / Baldor‑Reliance)

• Series: Legacy DC & AC Drive Systems (MaxPak, FlexPak, HR2000, GV3000)

• Type: Tach Loss / Overspeed Protection Board

• Function: Monitors tachometer feedback signal; detects tach loss and overspeed conditions; provides fault relay output and system inhibit for drive safety

• Status: Obsolete (legacy); refurbished / NOS available

• Mounting: 3U Eurocard for CardPAK rack or chassis mount

• Alternate IDs: NSN 5998‑01‑217‑1441

2. Electrical Specifications

• Backplane Supply: ±15 VDC, +24 VDC (auxiliary)

• Power Consumption: ≤ 8 W

• Tach Input:

  • Signal: 0–10 VDC (tachometer voltage)

  • Impedance: > 10 kΩ

  • Calibration: Onboard “Tach Cal” trimpot

• Speed Reference Input: 0–10 VDC (for overspeed comparison)

• Fault Thresholds:

  • Tach Loss: < 2% of rated tach signal (adjustable)

  • Overspeed: 105–120% of reference (adjustable)

• Outputs:

  • Fault Relay: 24 VDC, 1 A (NO/NC)

  • Inhibit: 24 VDC logic (active low)

• Indicators:

  • Tach LED: Green (ok) / Red (loss)

  • Overspeed LED: Red (fault)

• Reset: Front‑panel momentary pushbutton (manual reset)

• Isolation: 1500 VAC (control‑to‑power)

• Terminal Strip: 12‑position screw terminal (field I/O)

3. Mechanical Specifications

• Form Factor: 3U Eurocard (19” rack compatible)

• Dimensions (W×H×D): 100 mm × 160 mm × 35 mm (including front panel)

• Weight: ~0.55 kg (~1.2 lb)

• Construction:

  • Conformal‑coated PCB (industrial grade)

  • Metal front panel with calibration pot, LEDs, reset button, 12‑pin terminal strip

  • Gold‑finger edge connector (backplane interface)

• Key Components:

  • Transformer (TR‑12174)

  • 6× ICs, 6× transistors, relays, discrete components

4. Environmental Ratings

• Operating Temperature: 0 °C to +55 °C

• Storage Temperature: −20 °C to +70 °C

• Humidity: 10%–90% RH, non‑condensing

• Vibration: 10–100 Hz, 0.15 mm amplitude (operational)

• Certifications: UL, CSA, CE (legacy approvals)

5. Key Features

• Dual fault protection: Tachometer signal loss + overspeed detection

• Adjustable thresholds: Tach loss sensitivity and overspeed trip point via trimpots

• Front‑panel diagnostics: Clear LED status + manual reset button

• Isolated fault relay: Safe drive shutdown on critical faults

• Compact 3U form factor: Fits standard CardPAK racks; hot‑swap capable

• Industrial durability: Conformal coating, wide temperature range, vibration resistance

6. Compatibility

• Racks: CardPAK 6‑slot / 12‑slot / 18‑slot; MaxPak / FlexPak chassis

• Drives: Reliance MaxPak Plus, HR2000, FlexPak, MinPak, GV3000 DC/AC drives

• Interchangeability: 528061 / 0‑52806‑01 fully interchangeable