braking resistor parameter

kindly, we need to know the following "parameter" for the below braking resistor. any idea how to calculate it? or where can we find it?

"The thermal transient response of the external dynamic brake resistor defined by the maximum allowable power to the dynamic brake resistor for 1 second without exceeding the resistor’s element temperature."


6SE6400-4BD26-0FA0
SINAMICS BRAKING RESISTOR 380-480V 5,5R 120000W PK 5600W CONT 526 X 484 X 301 MM H X W X D IP20


https://support.industry.siemens.com/cs/pd/213635?pdti=td&lc=en-QA

Not sure you can calculate it. At least not accurately. It'll likely take an experiment to arrive at the correct figure.

How much power do you need to push thru' the resistor? And is it one second bursts or is the peak part of a ramp up and down? What kind of duty cycle are you looking for?

Answer those questions then make an educated guess based on where your answers fall between the manufacturers continuous and peak KW numbers.

the power is sent to the resistor during a ramp down of 10 seconds. the motor has a rated power of 132 kw, but it is consuming maximum 100 A.

comparing to the below other brand, can we estimate the value? around 1086.2 kW-s?

Braking resistor 6.0 Ohms , 7,776 Watts , 1086.2 kW-s , Encl P/N GCE15 , Dimensions 26.5W x 16D x 5H Rockwell PR5505-19A

Figuring wattage for brake resistors is a tricky business. In addition to the short-term wattage found by multiplying voltage by short-term amps, you have the time element. Not only the time the braking resistor is energized but the time between cycles when the resistor is cooling down.

We always figured that a resistor is good for ten times its continuous wattage for one minute if starting cold. Clearly, if not fully cooled from the previous cycle, the short-term rating will be lower.

I've seen brake resistors lit up like light bulbs but you have to be careful with resistors that hot. If the are seldom used and are covered with dust (or worse), you will start a nasty fire in the resistor bank.

to be safe, i have put the parameter value equal to half the competitor's, which will be 500 000 watt-second. now the machine is running ok. to be monitored. thanks