| AC tachogenerator | DC tachogenerator |
|---|---|
| The AC tachogenerator is use to measure speed only in one direction only. | The DC tachogenerator is use to measure speed in both direction. |
| It consists of a stator and a rotor arrangement or a squirrel cage setup. | It consists of horse shoe type permanent magnet. |
| Need of rectifier to convert AC output into DC. | Output is in DC form therefore no need of rectifier. |
| No problem of brush friction and brush bounce. | Problem of wear and tear brushes at high speed. |
| Ripples are reduced. | Small ripples are appearing at output. |
| Maintenance is difficult. | Easy to maintenance. |
AC tachogenerator
 AC tachogenerator |
DC tachogenerator
 DC tachogenerator |
Difference between AC tachogenerator and DC tachogenerator
