Here's a summary of Recent News and New Things happening at DENT Instruments:
In this issue...
- REAL WORLD APPLICATIONS: Cellular Modem Application Note
- TIPS & TRICKS: Establishing a Proper Connection for 3 Phase Open Delta
NEW Cell Modem for ELITEpro Application Note Available for Download
Our New Application Note describes remote communications with the ELITEpro and DATApro data loggers using an external Data Remote 9060 Cell Modem. The advantages of using a cellular modem include eliminating the need to travel long distances to a remote device and allowing wireless data collection when landlines are unavailable or cost-prohibitive.Check out the New Cell Modem Application Note (PDF) here!
Configuring a Proper Connection for a 3 Phase Open Delta
Question:What is the proper connection for a 3 phase open delta?
Answer from Mike Leno:
The open Delta Configuration is usually used in remote well pump locations. Two phase legs and a MGN (multi-grounded-neutral) are connected in open Delta. This provides 240VAC three phase for a pump or motor. This is a cost savings measure since there is one less power line and one less transformer in the system.
You can use a single phase three wire setup table or a Wye table to meter this circuit. You would place CTs on the two ungrounded lines (L1, L2). Since this is a three element system, a two CT method should adhere to Blondel's Theorem and meter correctly. If you use a WYE method with three CTs, it would just meter zero on one of the channels, but the system totals should be correct. Make sure that your CTs match the correct voltage leads of the logger (CH1/L1, CH2/L2).