kalo saya biasa pake part yang seperti ini buat pengaman motor 3phasa
Siemens 3RV1 Motor Breaker
Siemens 3RU1 Overload Relay
Siemens 3RB2 Motor Protection Relay
■ 3RV1 Motor Breaker: Overload Relay + Short Circuit Protection (upto 100kA)
■ 3RU1 Overload Relay: Thermal Overload Relay (Class 10)
■ 3RB20, 21 Motor Protection Relay: Solid State Overload Relay (Class 10, 20,)
■ 3RB22, 23 Motor Protection Relay: Solid State Overload Relay (Adjustable Class)
■ Basic Module Required: Evaluation Module + CT Module
■ Add-on Modules: Analog Output Module / Ground Fault Module
■ Protection: Class 10 / 20 / 30, Overload Protection & Thermistor Motor Protection
Download Catalog-->>
http://www.nce.com.hk/download/siemens/Siemens-3RV-3RU-3RB-Overload-Protection-Device-2009.pdf