1 / 10

Series-Impedance Starting

Series-Impedance Starting. Impedance Z is either an Inductor or a Resistor to limit the current during start-up. Series-Impedance Starting continued. Select the resistor or inductor (reactor) to provide about 70% rated voltage. Simplest method for starting. Example 5.20.

cedric-mccall
Download Presentation

Series-Impedance Starting

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Series-Impedance Starting ECE 441

  2. Impedance Z is either an Inductor or a Resistor to limit the current during start-up ECE 441

  3. Series-Impedance Starting continued • Select the resistor or inductor (reactor) to provide about 70% rated voltage. • Simplest method for starting ECE 441

  4. Example 5.20 • A 30-hp, wye-connected, three-phase, 230-V, 60-Hz, 78-A, 1748 r/min, design B motor has a locked-rotor impedance per phase of 0.273 /69°Ω at rated temperature and frequency. The motor is to be started using series resistors in each line. Determine • a) the resistance of the resistors required to limit the locked-rotor current to three times rated current ECE 441

  5. Example 5.20 continued • The circuit configuration is shown here ECE 441

  6. ECE 441

  7. Example 5.20 continued • Apply Ohm’s Law to one branch ECE 441

  8. Example 5.20 continued • b) the stator voltage/phase at locked-rotor ECE 441

  9. Example 5.20 continued • c) The expected minimum locked-rotor torque at rated when starting as a percent of rated torque. • Minimum locked-rotor torque at rated voltage and frequency is 150% rated torque (Table 5.1) ECE 441

  10. Example 5.20 continued • Note – Calculations must be made on the actual voltage applied to the stator. ECE 441

More Related