RE7557 Brushless Resolver (Size 30)



Size 30 Frameless Resolver (3″ or 75mm OD)

The Micronor RE7557 series frameless Brushless Resolver provides high performance in measurement and feedback applications where traditional resolvers fail – high speed, vibration, shock and radiation environments.  This resolver is designed for the most demanding harsh environment applications – including Aerospace, Space, Automotive, Marine, Submarine, Radiation, and Downhole.

The REXXXX series incorporate a proprietary solid rotor design with no windings. Hence, the resolver has only half the number of windings of a traditional brushless resolver, along with significantly increased reliability. The solid rotor allow operation with traditional oils or other liquids.


Parameter Value
Type Control Transmitter (Rotor=Excitation Input, Stators=Sine/Cosine Output)
Size Size 30 (3″ or 75mm OD), 75mm OD x 57mm H
Bore 46mm ID
Max Speed Standard=25,000rpm
High Speed= 28,000rpm
Temperature Rating Standard= -40°C to +135°C
High Temperature= -70°C to +200°C
Accuracy +/- 60 arcmin
Excitation Frequency 1-10 kHz, 8 kHz typical
Transformation Ratio 0.5 (+/-10%)
Speed 1 (1 pole-pair)
Radial Air Gap 0.3mm (special gaps to 1mm available)
Shock Resistant 20 G
Vibration Resistant 10-50 Hz, 10 G over 0.5 hrs
Radiation Resistance Standard with High Temperature models

Ordering Information

Type Specifications Part Number
Standard Temperature, Standard Speed -40°C to +135°C, max 25’000rpm RE7557-1-1
Standard Temperature, High Speed -40°C to +135°C, max 28’000rpm RE7557-1-2
High Temperature, Standard Speed, Radiation Resistant -70°C to +200°C, max 25’000rpm
and Radiation Resistant
High Temperature, High Speed, Radiation Resistant -70°C to +200°C, max 28’000rpm
and Radiation Resistant


  • Compact Size 30 (3″ or 75mm OD)
  • Standard bore, 46mm ID
  • Solid rotor design offers higher reliability than traditional wired resolvers
  • For harsh environment applications where traditional resolvers fail
  • Max Speed, 28,000 rpm
  • Max Temperature Range, -40°C to +200°C
  • High Temperature models are also Radiation Resistant
  • Excitation =1-10kHz, Transformation Ratio=0.5, Single Speed
  • Special Bore sizes and Higher Speeds available upon request 


  • Aerospace
  • Flight control systems
  • AC or DC servo motor feedback
  • Hydraulic pumps
  • Downhole
  • Automotive and race cars
  • High-speed spindles/li>
  • Nuclear environments (special Radiation Resistant models available)


RE7557 Datasheet
RE7557 2D Drawing


Call +1-805-389-6600 or email