Yaskawa FSP Amplifier - Manual (Page 361)

FSP Amplifier User’s Manual Appendix E: External Regenerative Resistor Specifications
E-2
When power resistors are used at the rated load ratios, the resistors operating
temperature rises to between 200ºC and 300ºC. The resistors must be used at values
below the rated values. Check with the manufacturer for resistor load characteristics.
Use resistors at no more that 20% of the rated load ratio with natural convection
cooling, and no more that 50% of the rated load ratio with forced air cooling. For
example, if a JUSP-RA04 is used in its factory configuration of 6.25 Ω, The
allowable capacity is 176 W (20% of 880 W) with natural convection cooling. In
forced-air cooling it is 440 W (50% of 800 W). User parameter Pn600 must be set to
the allowable capacity for the regenerative circuit in the FSP amplifier to operate
properly.
Yaskawa’s External Regeneration Units P/N JUSP-RA04, -RA05, -RA18, and -RA19
may also be rewired to achieve the needed equivalent resistances and power
capacities. The rewiring procedure includes the removal of jumpers J1 and J2, and use
of spare screw terminals P1 and P2. The examples below describe the modification of
JUSP-RA04 to provide 440 W of regenerative power capacity at 12.5 Ω , 880 W at
6.25 Ω, and of the JUSP-RA05 to provide 1760 W at 3.12 Ω. Please note that these
power capacities are before derating. Refer to the above paragraphs for the proper
derating level.
Yaskawa’s External Regenerative Resistor P/N RH500N25ohmK (25 Ω, 300 W) and
P/N RH12050ohmJ (50 Ω, 70 W) may also be used in single or multiple units in
either series or parallel combinations to achieve the needed equivalent resistances and
power capacities.