EM4/EM7 Specifications

The EM4 and EM7 electromagnets have been discontinued.

Typical field uniformity (EM4 magnet)

Magnet configuration Uniformity
over 1 cm3
1% cylindrical volume
Pole cap
cm (in)
Air gap
cm (in)
Diameter
cm (in)
Length
cm (in)
10 (4) 5 (2.0) ±0.15% 1.8 (0.7) 5.0 (2.0)
10 (4) 2.5 (1.0) ±0.05% 6.5 (2.5) 2.5 (1.0)
7.6 (3) 2.5 (1.0) ±0.06% 4.6 (1.8) 2.5 (1.0)
5 (2) 2.5 (1.0) ±0.35% 1.8 (0.7) 2.5 (1.0)
5 (2) 1.3 (0.5) ±0.16% 3.6 (1.4) 1.2 (0.5)

The third column gives uniformity over one cubic centimeter volume centered in the magnet cap. The last two columns give the cylindrical volume within which the magnetic field deviates by less than 1% from the central field. The cylindrical volume is coaxial with the magnet poles and centered in the gap.

Typical field uniformity (EM7 magnet)

Pole cap
cm (in)
Air gap
cm (in)
Uniformity
15.2 (6) 5 (2) Better than ±0.1% over centered 2 in diameter circle
7.6 (3) 3.8 (1.5) Approximately ±0.1% over centered 1 in diameter circle
  EM4-HVA EM7-HV
Air gap Up to 11 cm (4.3 in) continuously variable Up to 17.8 cm (7 in) continuously variable
Nominal coil resistance 0.25 Ω per coil (0.5 Ω wired in series) 1.0 Ω per coil (0.5 Ω wired in parallel)
Standard pole cap diameter 5.1 cm (2 in) 7.6 cm (3 in)
Optional pole cap diameter 2.5 cm, 7.6 cm, 10.2 cm (1 in, 3 in, 4 in) 15.2 cm (6 in)
Cooling water Tap water or closed cooling system
Water flow rate 7.6 L/min (2 gal/min) 11.4 L/min (3 gal/min)
Pressure drop 200 kPa (30 psi) 220 kPa (32 psi)
Water chiller cooling capacity 2.5 kW (8,530 BTU/h) 8.3 kW (28,321 BTU/h)
Water inlet temperature 15 °C to 25 °C (59 °F to 77 °F) 15 °C to 32 °C (59 °F to 89 °F)
Coil over temperature limit 45 °C (113 °F)
Coil spacing, nominal 12 cm (4.75 in)   17.8 cm (7 in)
Coil size-width, nominal 12 cm (4.75 in)   13.2 cm (5.2 in)
Coil size-diameter, nominal 31.1 cm (12.25 in)   44.5 cm (17.5 in)
Current (maximum continuous operating) ±70 A (in series) ±67.5 A (in parallel)
Voltage ±35 V nominal ±75 V nominal
Maximum continuous input power 2.5 kVA nominal 9.1 kVA nominal
Lake Shore power supply (suggested) Model 643 Model 648
  Size
Height 38.7 cm at 40° angle (15.25 in) without stand 94 cm (37 in)
Width 84.5 cm (33.25 in) 101.6 cm (40 in)
Depth 50.8 cm (20 in) 66 cm (26 in)
Weight 201.9 kg (445 lb) 614 kg (1350 lb)
Shipping weight 215.5 kg (475 lb) 660 kg (1500 lb)
Shipping dimensions 95.5 cm × 58 cm × 56 cm
(38 in × 23 in × 22 in)
86 cm × 122 cm × 119.4 cm
(34 in × 48 in × 47 in)

Electromagnet field plots and schematics