Ohm Checking the Simodrive Power Section
Caution! It must be assured that power is removed and the DC Bus has drained to a safe level before any connections are removed or checked!
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After you are sure that the DC Bus has safely discharged , a DVM on the Diode scale can be used to detect if a short circuit or open exists in the power section. Readings will vary with module size.
Note: P600 and M600 are the 600 V DC Bus connections. U2, V2 and W2 are the motor connections.
• Disconnect the P600, M600 bus bars, U2, V2 and W2 connections. This isolates the power module from the motor and DC Bus.
• Diode check between P600 and U2, then V2 then W2. There should be continuity with the – lead on P600 and the + lead on U2, V2 or W2. Readings should be open with the leads reversed.
• Diode check between M600 and U2, V2, W2. There should be continuity with the + lead on M600 and the – lead on U2, V2 or W2. Readings should be open with the leads reversed.
• Diode check between P600 and M600. There should be continuity with the + lead on the M600 and the – lead on P600. The reading should be open with the leads reversed.
• Diode check between U2, V2 and W2. All combinations should read open.
Note: If all readings are open the internal DC Bus fuse is open. If there is a 0Ω reading, there is a short in the power circuit.
Note 2: Because of the capacitance in the power circuit, resistance checks will indicate a charging effect. It is necessary to wait until the measurement has stabilized to determine if it is correct. If possible, it is best to use a DVM with a diode check.
For more info you can visit our website to see all our Siemens Simodrives or email sales@mroelectric.com.
Updated on May 20, 2019 by Brian Hughes
