Description
1. At-A-Glance Executive Brief
- Model: PSTB720-600-70
- Brand: ABB
- Part Type: Digital Softstarter (PSTB Series)
- Lifecycle Status: Mature / Legacy Support Phase
- Weight: 55 kg
- System Compatibility: In-line or Inside-Delta Motor Configurations
2. Technical Introduction
Plant engineering groups managing high-horsepower industrial drives face significant mechanical shock and grid voltage sags whenever large motors start across the line. Finding a dependable high-amperage soft starter without forcing an entire motor control center redesign is essential for maintaining plant output. The ABB PSTB720-600-70 integrates microprocessor-based digital control algorithms and built-in bypass contactors into heavy-duty switchgear setups to manage acceleration ramps, limit starting currents, and eliminate water hammering on large fluid transport systems.
3. Core Technical Specifications
| Parameter | Value |
| Manufacturer | ABB |
| Product Series | PST(B) Advanced Range |
| Rated Operational Current | 720 A |
| Rated Operational Voltage | 208 to 600 V AC |
| Control Supply Voltage | 100 to 250 V AC, 50/60 Hz |
| Motor Power Capacity | 400 kW (at 400V) / Inside Delta support available |
| Built-in Bypass | Integrated (Standard on PSTB from 370A up) |
| Enclosure Protection | IP00 (Main Terminals) |
| Operating Temperature | 0°C to 50°C |
4. Field Engineer’s Tech Notes
- Internal Bypass and Heat Dissipation: Because this unit features an integrated mechanical bypass contactor, verify that internal bypass relays transition cleanly at the end of the start ramp. Failure of the bypass transition will subject the internal thyristors to continuous thermal stress, leading to premature semiconductor failure.
- Busbar Torque and Cabling: The main power terminals rely on heavy-duty bar connections. Torque all high-voltage cable bolts strictly to the OEM specification (45 Nm) using a calibrated wrench. Loose high-amperage terminations generate localized thermal hot spots that will trip thermal sensors or damage the bus assembly.
5. Adaptive QA & Testing Protocol
Our testing routine for high-power semiconductor soft starters utilizes dedicated high-current simulation test benches. For this 720A unit, technicians execute control board logic checks, digital keypad navigation tests, auxiliary relay output verification, and integrated bypass contactor actuation cycles under a controlled low-voltage load. Thyristor voltage drop and triggering synchronization are verified via oscilloscope. Detailed functional test logs and verification videos are available upon request.
6. Buyer’s FAQ
- What warranty is included with this soft starter unit? All units are backed by a 12-month operational warranty from the date of invoice.
- How is this heavy unit shipped for urgent plant replacements?Due to the 55 kg net weight, the unit is bolted to a custom wooden pallet and dispatched via priority freight carriers to ensure safe delivery.
- Is this unit supplied as New Surplus or Refurbished? We stock both verified New Surplus (NSFP) and factory-refurbished configurations. Specific inventory conditions are verified prior to shipment.
