3500/53 Overspeed Detection — electronic overspeed protection

Description

The 3500/53 is the Electronic Overspeed Detection System module for the Bently Nevada 3500 rack: a fast, redundant tachometer intended for use as part of a turbine overspeed protection system, designed to API 670 and API 612.

Several 3500/53 modules are combined into 2-out-of-2 or 2-out-of-3 (recommended) voting. A 3500 rack with dual 3500/15 power supplies is required.

Status. According to Bently Nevada (datasheet 162242), the 3500/53 is replaced by the SIL 3 certified 3701/55 ADAPT.ESD for new installations. KEG TRK supplies the 3500/53 for existing racks and offers the 3701/55 for new projects.

Specifications (datasheet 141539, Rev. G)

Parameter	Value
Input	1 speed transducer per module, +10 V to −24 V, 20 kΩ input impedance
Transducers	3300, 3300XL, 7200, 3300 RAM, 3300 16 mm HTPS Proximitor; magnetic pickups
Range	up to 99,999 rpm, 1–255 events per revolution, input up to 20 kHz
Minimum frequency	0.0167 Hz for proximity (1 rpm), 3.3 Hz for magnetic pickups
Accuracy	±0.1 rpm (< 100 rpm), 1 rpm (100–10,000), ±0.01 % (10,000–99,999)
Alarm delay	under 30 ms above 300 Hz
Relays	SPDT, epoxy sealed, up to 5 A; 30 Vdc / 250 Vac
Recorder output	4–20 mA proportional to speed; not for the governor
Transducer power	−24 Vdc, 40 mA max
Power consumption	8 W typical
Operating temperature	−30 to +65 °C (storage −40 to +85 °C), humidity up to 95 %

Applications

• steam and gas turbines in power generation and mechanical drive;
• turboexpanders and turbocompressors at gas processing plants;
• any machine where API 670/612 requires overspeed protection separate from the governor.

Supply in Kazakhstan

KEG TRK supplies 3500/53 modules and spares for existing 3500 racks and helps configure voting and verify setpoints. For new projects we offer the 3701/55 ADAPT.ESD.