Appendix A
Dynamic Brake
230VAC 1 & 3 Phase Controls All controls are supplied without braking resistors.
Size 1 and 2 – 230VAC 1 Phase
Size 1 and 2 230VAC controls have no external dynamic brake capability.
Size 3 – 230VAC 3 Phase
Size 3 230VAC controls have internal brake circuit and can accept external brake resistor.
460VAC 3 Phase Controls
Size 2 and 3 – 460VAC
Size 2 and 3 460VAC controls have internal brake circuit and can accept external brake resistor. The dynamic brake circuit is designed for short term stopping or braking only. It is not rated for a continuously overhauling load. All controls are supplied without braking resistors. The dynamic brake switch terminals allow easy connection of an external resistor. These resistors should be mounted on a heatsink (enclosure panel) and covered to prevent severe buring.
Brake Calculations
Brake assemblies must be rated to absorb the peak brake power during deceleration and the average power over the complete cycle.
Ppk |
| 0.0055 x J x (n12 * | n22) |
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| tb | (W) |
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Pav | + | Ppk | x tb | 120 |
| Resistor Derating Graph |
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tc | 100 |
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| 80 |
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| free air |
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| % of Rated |
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| 60 |
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| Power |
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| 40 |
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| 20 |
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| 0 |
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| 0 | 25 | 50 | 75 | 100 | 125 | 150 | 175 | 200 |
where: | J = | Ambient Temp (C) |
total inertia (kgm2) | ||
| n1 = | initial speed (RPM) |
| n2 = | final speed (RPM) |
| tb = | brake time (seconds) |
| tc = | cycle time (seconds) |
The minimum resistance of the combination (series/parallel resistor connections) must be as specified in Table
RGA and RGJ Assemblies
Assemblies include braking resistors completely assembled and mounted in a NEMA 1 enclosure. A listing of available resistor assemblies is provided in Table
MN735 | Appendix |
