MEGGER BA185 Current Transformer Burden Ammeter

The BA-185 Current Transformer Burden Ammeter is a rugged, portable instrument, designed to field-test current transformer installations for:

• Short-circuited secondary turns
• Short-circuited primary turns
• Short-circuited secondary wiring
• High-resistance connections in the secondary circuit
• Grounding of secondary winding when mounted on a grounded structure
• Grounding of a normally ungrounded wire

Within the accuracy limits of the CT, a good current transformer should not have a noticeable change in ratio when a secondary burden is added. This is because the primary effect of additional burden on a good CT is a ris in the secondary voltage. However, if one or more turns of a CT are shorted, a substantial amount of the total available ampere-turns is diverted into the shunt path created by the short.

Thus, the current to the circuit connected to the CT is less than the CT’s total secondary current. Therefore, when the proper burden within the ammeter is added in series with the circuit connected to a good CT, the current indicated by the ammeter should only decrease a few percent.

MEGGER BA185 Specification:

• Ammeter Ranges: 1.25, 2.5, 5 and 10
• Burdens (ohms): 0.25, 0.5, 1, 2 and 4
• Burden Ratings (VA at a nominal current of 5 amperes): 6.25, 12.5, 25, 50 and 100