Chapter 7 Optional Accessories MS300 (High Speed Model) * 1 Standard braking torque is 125 %. Because of the limited resistor power, the longest operation time for 10 % ED is 10sec. (on: 10 sec. / off: 90 sec.). * 2 Please refer to the Brake Performance Curve for “Operation Duration & ED (%)” vs. “Braking Current”. * 3 Calculation for braking torque is for a 4-pole motor 1800 rpm. * 4 Resistors of 400 W or lower should be fixed to the frame and at a surface temperature below 50 °C. Resistors of 1000 W and above should be fixed on a surface with temperature below 350 °C NOTE 1. Please select the resistance value, power and brake usage (ED %) acc. to Delta rules.
Definition for Brake Usage ED % Explanation: ED (%) is defined to allow enough time for the brake unit and brake resistor to dissipate the heat generated by braking. Recommended cycle time T0 is one minute. For safety concern, install a thermal overload relay (O.L) between the brake unit and the brake resistor in conjunction with the magnetic contactor (MC) before to the drive for additional protection. The purpose of the thermal overload relay is to protect the brake resistor from damage due to frequent or continuous braking. Under such circumstances, just turn off the power to prevent damaging the brake resistor, brake unit and drive. 2.
If the drive or other equipment is damaged due to the fact that the brake resistors and brake modules in use are not provided by Delta, warranty will be void. 3. Take the safety of the environment into consideration when installing the brake resistors. If the minimum resistance value is to be used, consult local dealers for the calculation of the power. 4. When using more than 2 brake units, equivalent resistor value of parallel brake unit can’t be less than the value in the column “Minimum Equivalent Resistor Value for Each AC Drive” (the right-most column in the table). Please read the wiring information in the user manual of brake unit thoroughly prior to operation 5.
Thermal Overload Relay (TOR): To choose a thermal overload relay is based on its overload capacity whether is appropriate to MS300. The standard braking capacity of MS300 is 10 % ED (Tripping time=10s). As shown in the figure below, thermal overload relay continuously operates for 10 sec. and it can stand 260 % overload (Host starting). Take a 460V, 15 kW of MS300 as an example, its braking current is 24A (refer to the table on page 7-3), thus it can use the thermal overload relay which rated current is 10A (10*260 % = 26A > 24A). 40 30 60 20 10 Tripping time 8 6 4 3 2 1 0.8 0.6 0.4 0.3 0.8 1 1.5 2 3 4 5 6 8 10 15 7 9 Multiple of current setting xln (A) 7-3 Second