IEVref: | 351-50-18 | ID: | |||||||||||||||

Language: | en | Status: Standard | |||||||||||||||

Term: | derivative action gain | ||||||||||||||||

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Definition: | for a proportional plus derivative element with an additional first-order lag the ratio of the maximum gain resulting from the proportional plus derivative action with first-order lag to the gain resulting from proportional action only SEE: Figure 18. Note 1 to entry: The transfer function of a PD element with first-order lag is $\frac{V\left(s\right)}{U\left(s\right)}={K}_{\text{\Rho}}\cdot \frac{1+{T}_{\text{d}}\cdot s}{1+{T}_{1}\cdot s}$ and using the derivative action gain $\frac{V\left(s\right)}{U\left(s\right)}={K}_{\text{\Rho}}\cdot \frac{1+{T}_{\text{d}}\cdot \text{s}}{1+\frac{{T}_{\text{d}}\cdot s}{a}}$ where
Note 2 to entry: This entry was numbered 351-28-29 in IEC 60050-351:2006. | ||||||||||||||||

Publication date: | 2013-11 | ||||||||||||||||

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SEE: Figure 18.

Note 1 to entry: The transfer function of a PD element with first-order lag is

$\frac{V\left(s\right)}{U\left(s\right)}={K}_{\text{\Rho}}\cdot \frac{1+{T}_{\text{d}}\cdot s}{1+{T}_{1}\cdot s}$

and using the derivative action gain *a* = *T*_{d}/T_{1} the transfer function may be written

$\frac{V\left(s\right)}{U\left(s\right)}={K}_{\text{\Rho}}\cdot \frac{1+{T}_{\text{d}}\cdot \text{s}}{1+\frac{{T}_{\text{d}}\cdot s}{a}}$

where

K_{P} | is the proportional action coefficient; |

T_{d} | is the rate time; |

T_{1} | is the time constant; |

a | is the derivative action gain, 1 < a < ∞; |

s | is the complex variable of the Laplace transform; |

U(s) | is the input transform; |

V(s) | is the output transform. |

Note 2 to entry: This entry was numbered 351-28-29 in IEC 60050-351:2006.