The Silent Partner Max (SPMAX) logger is a safe, easy to operate logging solution for residential and commotional use. Completely housed in Rugged, watertight construction means that the logger is resistant to harsh environments and vandalism. The SPMAX measures line to neutral, 3 current channels power factor. With the addition of a pulse input to read 3rd party pulse output meters, the SP Max becomes an extremely attractive choice for power monitoring. Internal rechargeable batteries continue logging in the event of a power failure.


  1. 12 Bit Resolution
  2. ± 0.25% Accuracy
  3. Measure 3 current, 1 voltage, 1 power factor, 1 dry contact pulse input
  4. Downloads with Silent Partner Pro Windows® software
  5. -40°C temperature range for extreme weather conditions


  1. Energy Studies
  2. Industrial Monitoring
  3. Machinery and motor analysis
  4. HVAC studies
  5. Electrical Utilities



Maximum Channels Six Selectable storage for each channel.
Ranges Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 6
0 - 275 VAC
0 - 1 VAC - Current CT Input
0 - 1 VAC - Current CT Input
0 - 1 VAC - Current CT Input
0 - 180° Channel 1 to Channel 2
Pulse input from dry contacts
True RMS for 50/60 Hz. operation.
Pulse input is used for dry or voltage free contacts only.
Other voltage ranges available - contact Northwood for details.
Power factor calculated via software (Cos q).
External Connections Isolated USB, Aux. power, 3 current, 1 voltage, 1 pulse.  
Sensor Type External CT’s, internal impedance network for voltage.  
Sample Rate ¼ Second.  
Storage Rate 1 second to 15minutes. Set via Silent Partner Pro software Windows®.
Parameters Stored Average, Min/Max, or Min/Max/Average. Set via Silent Partner Pro software Windows®.
Memory 512K bytes. Non-volatile flash memory.
Memory Treatment Stop when full, or wrap. Set via Silent Partner Pro software Windows®.
Storage Capacity 512K 512K Total
Indicators LED's for: Line Power, Over/Under/Phase, Over current.  
Power Line Power, Internal battery, external adapter. Internal battery recharged via line or external adapter.
Battery Life 14 Days (can also operate from external adapter). Lead-foil battery.
Communications Isolated USB, support for remote setup.  
Software Silent Partner Pro software for Windows®. Requires PC running Windows 32Bits and 64Bits.
Packaging Water tight (with meter affixed). Rugged, durable ABS. All components conformal coated.
Accuracy ± 0.25 % Range + CT error (Full Scale).  
Resolution 0.1V, 0.1A 12-bit A/D converter.
Safety Optically isolated download, CSA Special Inspection.  
Weight 3.25 lbs.  
Dimensions 6" diameter x 5" deep (6" dia. X 6" for -40° model).  
Environmental -40°C to 60°C (- 40°F to 140°F) extended temp range, Relative humidity - to 90% non-condensing.  

Specifications subject to change without notice.