Time Mark

Time Mark 257B 3-Phase Monitor

Name: Time Mark 257B 3-Phase Monitor
Brand: Time Mark
SKU: 98083702
Price: 74.37 USD
Availability: InStock

In stock

SKU: 98083702

$74.37 inc. VAT

Product variants

3 Phase Power

Electromechanical relay
Solid-state voltage
Phase-angle sensing circuit
For abnormal conditions

The Model 257 continuously monitors 3- phase power lines for abnormal conditions. When properly adjusted, the Model 257 monitor will detect phase loss on a loaded motor even when regenerated voltage is present.

This device consists of a solid-state voltage and phase-angle sensing circuit, driving an electromechanical relay. When correct voltage and phase rotation are applied, the internal relay will energize. A fault condition will de-energize the relay. When the fault is corrected, the monitor will automatically reset (a manual reset version is also available).

The Model 257 does not require a neutral connection and can be used with Wye or Delta systems. Voltage ranges are sufficiently wide to allow for proper adjustment to existing conditions. Both "TRIP" and "NORM" condition indicators are provided to aid in adjustment and system trouble-shooting.

Typical Application	Dimensions

Manuals/Guides

Manufacturer Specs

General Specifications
AUTO Reset MANUAL Reset	B257B B257BM	257B 257BM	A257B A257BM	EX257B EX257BM	B257B-400 B257BM-400	257B-400 257BM-400	EX257B-415V EX257BM-415V
Nominal AC (phase to phase)	120VAC	208/240VAC	480VAC	380VAC	120VAC	208/240VAC	415VAC
Case Color	Gray	Red	Yellow	Yellow	Gray	Red	Yellow
Adjustment range	85-120VAC	160-240VAC	380-480VAC	300-400VAC	85-120VAC	160-240VAC	340-440VAC
Frequency	60Hz	60Hz	60Hz	50Hz	400Hz	400Hz	50Hz
Power consumption	1.4W	2.4W	3.7W	3.0W	1.4W	2.4W	3.3W
Transient protection	2500VAC for 10ms
Repeat accuracy	± 0.1% of set point (fixed conditions)
Response time	50ms drop out
Dead band	Approximately 2%
Output contacts	SPDT 10 amps at 240VAC resistive
Expected relay life	Mechanical: 10 million operations Electrical: 100,000 operations at rated load
Operating temp	-20° to +131° F
Humidity tolerance	0 - 97% w/o condensation
Enclosure material	ABS plastic cover
Mounting	8-pin socket ( **sold separately)
Weight	5 ounces
Agency approvals	UL Recognized* and CSA Certified *Conditions of acceptability: (1) the 380V and 480V versions must be used with a UL Recognized 600VAC socket. (2) For use in a Pollution Degree 2 environment (3) To be installed on the load side of branch circuit protection rated 10A

Tech Specs

Three Phase Monitor Relays
3-Phase Monitor Relay Function	Phase Loss/Phase Reversal/Under Voltage Only
Max Nominal Phase to Phase Voltage (monitors)	240 VAC
Min Nominal Phase to Phase Voltage (monitors)	208 VAC
Electrical Approval (monitor relays)	CSA, UL
Time Mark Mounting	8-pin
Test Equipment General Attributes
Warranty	5 YEARS
Warranty Details	This product is warranted to be free from defects in materials and workmanship, and is covered by our exclusive 5-year Unconditional Warranty. Should this device fail to operate for any reason, we will repair it for five years from the date of manufacture.
Safety Approval	CSA, UL
Product Weight	0.475 LBS
Product Height	3.52 IN
Product Length	2.44 IN
Product Width	1.75 IN
HTS/Schedule B Number	8542.39.0001
ECCN Number	EAR99
Country of Origin	United States
UPC	00662917001657

Time Mark 257B 3-Phase Monitor

3 Phase Power

Manuals/Guides

Manufacturer Specs

Tech Specs

Three Phase Monitor Relays

Test Equipment General Attributes