Can Macromatic's 3 Phase Monitor Relays be used with Open Delta Systems?

Wednesday: December 2, 2015 : Three-Phase Monitor Relays


Can Macromatic's 3 phase monitor relays be used with open delta systems?


Yes, by following a few simple guidelines.

Here is an open delta schematic:


1. The phase monitor needs to connect to A,B,C….not GND or Neutral

2. Select the correct phase monitor using the Phase to phase voltage of the power system, not Phase to neutral or ground voltages.

3. Ensure that Actual Unbalance is within the acceptable range of the phase monitor relay selected for proper operation or use a relay that does not provide unbalance protection. Open delta systems are predisposed to higher levels of unbalance.


©2020 Macromatic Industrial Controls, Inc.

W134N5345 Campbell Drive
Menomonee Falls, WI 53051

800-238-7474 • 262-781-3366

Rep Login | Newsletter Sign Up | Articles | Employment | Privacy Policy | Sitemap
Knowledgebase General | Alternating Relays | Current Sensing Relays | Intrinsically Safe Barrier Relays | Liquid Level Control Relays | Seal Leak Relays | Three-Phase Monitor Relays | Time Delay Relays | Voltage Monitor Relays