Temperature rise: For continuous duty applications, generators are typically 80° C, 105° C or 125° C rise by resistance per NEMA MG-1. Standby ratings are either 105° C, 130° C or 150° C rise per NEMA MG-1. Rise is based on an ambient temperature of 40° C.

Overload: Typical allowable overloads are 50% for 5 minutes and 10% for 2 hours during 6 hours of operation. Short-circuit capability is at least 15 seconds at 300%.

Waveform: Generators are specifically designed to minimize harmonic distortion. Typical waveform characteristics are as follows:

  • Deviation factor: less than 5%
  • Crest factor: 1.3 - 1.5.
  • Harmonic content: any single harmonic is less than 3% and the total harmonic is less than 4%
  • Telephone influence factor (TIF): meets or exceeds NEMA MG-1-22.43 standards
  • Telephone harmonic factor (THF): meets or exceeds IEC 60034-1 requirements

Power factor: 0.8 Standard (other PFs available upon request)

Phase: 3

Voltage regulation: The voltage regulation can be from plus or minus 1/4% to plus or minus 2% depending on regulator choice. Kato manufactures a complete line of voltage regulators and accessories in accord with varying application requirements.

Voltage balance: With balanced loads, the voltage is held within 1.0% between phases.

Field excitation: Fast voltage response time to generator load changes with short time constant is provided with the kato brushless excitation systems. This allows the voltage regulator to react to changes in field excitation requirements. Three-phase high-frequency revolving armature excitation current is s full-wave rectified through six silicon- type rectifiers mounted in heat sinks and positioned in the air stream for maximum heat dissipation. Diode PIV rating is at least twice the peak operating voltage normally required.

Permanent magnet supplemental exciter: A separate permanent magnet rotating exciter (PMG) can be supplied, in addition to the brushless exciter, as an option.

Bearings: Bearings for machines up to 2000 kW are re-greaseable radial ball bearings, sized for 50,000 L10h life. For 2000 kW and over, grease lubricated split roller bearings and pressure or ring-oil lubricated sleeve bearings are available for all sizes. Spherical roller bearings or cylindrical roller bearings are used when there are special thrust, shock or radial load requirements.

Prime mover connections: Units with single-bearing designs may have either SAE flexible disk type couplings or forged flanged shafts for direct connection to engine flywheels. Generators with two-bearing designs have shaft extensions that are suitable for direct coupling to prime movers. Close-coupled SAE housing adapters are also available with both single and two-bearing designs.

Controls: When requested, KATO voltage regulators and other controls will be supplied to provide complete system compatibility.

Parallel operation: All Kato designed generators can operate in parallel with any generator when proper system coordination is made. Kato will assist the customer by providing all generator parameters needed for a system study. We offer consultation for the design of the generator requirements.

Certifications:
ABS
ATEX
DNV
Bureau Veritas
Lloyds
CSA
NKK
USCG 259
VDE
UL

Standards:
NEMA MG-1
IEEE 115
ANSI C50.12
BS 4999
CSA C22.2NO.100
IEC 34
API-546
ISO 9001
Australian AS 1359
Mil-Std-705

Tests: Generators are subjected to the following standard commercial tests in accordance with IEEE Std 115, NEMA MG-1, or Mil-Std-705 standards (Testing to IEC 60034, marine classification societies or other applicable specifications is available upon request):

  • Resistance on all windings (cold)
  • Insulation resistance on all windings
  • High potential test on all windings
  • Open-circuit saturation curve
  • Voltage balance on windings
  • Current balance on windings
  • Phase sequence
  • Mechanical balance (vibration)
  • Circulating current (when applicable)
  • Three-phase build-up short-circuit (conducted if the generator has a PMG or SBO)
  • Voltage transient at rated kVA (voltage regulation, stability, and response)
  • Regulator range (voltage adjust) test (if a regulator is supplied)

In addition to the standard tests, Kato can perform the following tests, which are usually done on the first unit of a new design or on special designs:

  • Open-circuit saturation with slip rings
  • Synchronous impedance curve (short-circuit saturation)
  • Zero power factor saturation curve
  • Summation of losses (efficiency tests)
  • Reactances and time constants
  • Overspeed
  • Voltage waveform (harmonic analysis)
  • Voltage modulation tests
  • Temperature rise test
  • Polarization index (stator)
  • Water-immersion and spray tests

Complete testing information is available upon request. Customers may witness test if prior arrangements are made.