4.5 Protection against energy hazards危險能量保護
4.5.1 Electrical energy hazards
Failure of any component within the PDS shall not release sufficient energy to lead to a hazard,
for example, expulsion of material into an area occupied by personnel.
Where appropriate, the possibility should be considered of energy transfer from the PDS motor
to the CDM/BDM when the driven equipment over-runs the CDM/BDM control.
NOTE There are no tests in this part of IEC 61800 for this requirement

4.5.2 Mechanical energy hazards機械危險能量
4.5.2.1 General
Mechanical failure due to critical speed considerations or torsional problems can create a
hazard to operating personnel. These considerations are applicable to all PDS, although they
are increasingly significant with increased equipment size, such as with high-voltage PDS. As
these subjects are application-dependent, it is not possible to include specific requirements in
this standard.

4.5.2.2 Critical torsional speed臨界扭轉轉速
Where appropriate, communication should be established between PDS/CDM/BDM supplier,
driven equipment supplier, installer, and user with respect to any anticipated critical torsional
speed considerations.

4.5.2.3 Transient torque analysis暫態轉矩(扭力)分析
Transient torque analysis is an important design tool for PDS to check torsional stresses in the
whole mechanical string. For example, the following operating conditions are areas of concern.
• start-up;啟動
• single-phase or three-phase short-circuit at the terminals of an a.c. motor;   單相或三相a.c.馬達端短路
• impact of possible commutation failure of an a.c. CDM;
• impact of the harmonic components of an a.c. CDM;
• field supply loss in a d.c. CDM;
• short-circuit at the armature terminals of a d.c. motor.     d.c.馬達端短路
Where appropriate, communication should be established with the driven equipment supplier
and the information required by 6.3.5.4 provided.

4.5.3 Acoustic noise emission噪音危險能量
Under consideration. Requirements for acoustic noise emission are often present in local
regulations. In the absence of such regulations, it is recommended that the limits of
IEC 60034-9 should be applied.