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EM-4V and EM-7V Electromagnets
Lake Shore
The Lake Shore EM-4V and EM-7V electromagnets (EM-V Series) produce magnetic fields with a variety of indexed air gap and pole cap configurations. The EM-V Series are ideally suited for integration into customer-designed magnetic test platforms for applications including magneto-optical studies, magnetic hysteresis studies, in-line annealing, Hall effect studies, susceptibility measurements, spin magnetic resonance demonstrations, and biological studies.
The EM-V series magnet coupled with a Lake Shore magnet power supply (MPS) and teslameter form a versatile laboratory electromagnet capable of producing magnetic fields up to 3.26 T and supporting very fast ramp rates of up to 1 T/s. This system, with true bipolar MPS power output, provides rapid uniform magnetic field ramping and field reversal to avoid discontinuities that occur during zero crossover when using unipolar power supplies.
ExactGAP™ indexed gap settings
The EM-V Series electromagnets feature ExactGAP™ indexed pole settings. The ExactGAP pole gap indexing makes it fast and easy to reconfigure the magnet gap for the required sample or option size without having to re-calibrate the magnet after changing the gap. Choose from 6 repeatable gap widths by unbolting the top plate and clicking the selector into place. The EM-V Series incorporate water-cooled coils and precision yokes made of magnetically soft, ultra-pure steel, assuring precise pole cap alignment as well as excellent field homogeneity and stability.
- Indexed pole gap settings (ExactGAP™) allow repeatable air gap changes without having to re-calibrate between changes
- Exceptional field intensities achieved with cylindrical or tapered pole caps
- Water-cooled coils provide excellent field stability and uniformity
- Removable pole caps facilitate variable pole face configurations and easy pole cap exchange
- Accurate pole alignment by precise construction of the air gap adjustment mechanism
- The EM-4V/EM-7V yoke designed for optimum air gap accessibility for both top and bottom of the magnet
- Compact size of the EM-4V permits convenient bench-top mounting
- Optional optical access pole caps available
EM-V Series Specifications
EM-4V typical field uniformity|
Magnet configuration |
Uniformity over 1 cm2 |
1% cylindrical volume |
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|
Pole cap |
Air gap |
Diameter |
Length |
|
|
102 (4.0) |
51 (2.0) |
±0.15% |
18 (0.7) |
51 (2.0) |
|
102 (4.0) |
25 (1.0) |
±0.05% |
64 (2.5) |
25 (1.0) |
|
76 (3.0) |
25 (1.0) |
±0.06% |
46 (1.8) |
25 (1.0) |
|
51 (2.0) |
25 (1.0) |
±0.35% |
18 (0.7) |
25 (1.0) |
|
51 (2.0) |
13 (0.5) |
±0.16% |
36 (1.4) |
13 (0.5) |
EM-7V typical field uniformity
|
Magnet configuration |
Uniformity over 1 cm2 |
1% cylindrical volume |
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|
Pole cap |
Air gap |
Diameter |
Length |
|
|
51 (2.0) |
16 (0.6) |
±0.11% |
28 (1.1) |
16 (0.6) |
|
51 (2.0) |
25 (1.0) |
±0.33% |
10 (0.4) |
25 (1.0) |
|
102 (4.0) |
16 (0.6) |
±0.03% |
74 (2.9) |
16 (0.6) |
|
102 (4.0) |
25 (1.0) |
±0.03% |
66 (2.6) |
25 (1.0) |
|
102 (4.0) |
38 (1.5) |
±0.05% |
48 (1.9) |
38 (1.5) |
|
102 (4.0) |
51 (2.0) |
±0.08% |
23 (0.9) |
51 (2.0) |
NOTE: The third column gives uniformity over one cubic centimeter volume centered in the magnet gap. 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.
General specifications
|
|
EM-4V |
EM-7V |
|
|
Air gaps |
With no pole caps |
57.5, 62, 70, 75, 78, and 100 mm |
|
|
|
With 2 in pole caps |
7.5, 12, 20, 25, 28, and 50 mm |
|
|
Coil resistance, nominal |
0.25 Ω per coil |
1.00 Ω per coil |
|
|
Coil resistance, cold |
0.23 Ω per coil |
0.92 Ω per coil |
|
|
Coil resistance, maximum |
0.27 Ω per coil |
1.08 Ω per coil |
|
|
Integrated pole diameter |
100 mm (4 in) |
178 mm (7 in) |
|
|
Available pole cap diameters |
50 mm (2 in) |
100 mm (4 in) and 50 mm (2 in) |
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|
Cooling water |
Tap water or closed cooling system |
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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) |
5.0 kW (17,060 BTU/h) |
|
|
Water inlet temperature |
15 °C to 25 °C (59 °F to 77 °F) |
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Coil over temperature limit |
45 °C (113 °F) |
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Coil spacing, nominal |
121 mm (4.75 in) |
178 mm (7 in) |
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|
Coil size-width, nominal |
121 mm (4.75 in) |
132 mm (5.2 in) |
|
|
Coil size-diameter, nominal |
311 mm (12.25 in) |
445 mm (17.5 in) |
|
|
Current (maximum continuous operating) |
±70 A |
±135 A |
|
|
Voltage, nominal |
±35 V (approximately 38 V at maximum coil temperature) |
±70 V (approximately 38 V at maximum coil temperature) |
|
|
Continuous input power, nominal |
2.5 kVA (2.65 kVA at max temperature) |
9.45 kVA (10.125 kVA at max temperature) |
|
|
Suggested power supply |
Lake Shore Model 643 |
Lake Shore Model 648 |
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|
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Size |
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Height |
77 cm (30.3 in) |
52.7 cm (20.8 in) |
|
|
Width |
78.7 cm (31 in) |
78.7 cm (31 in) |
|
|
Depth |
88.9 cm (35 in) |
88.9 cm (35 in) |
|
|
Weight of yoke and coils, no rolling base or pedestal, approximate |
227 kg (500 lb) |
567 kg (1250 lb) |
|
|
Weight |
201.9 kg (445 lb) |
635 kg (1400 lb) |
|
|
Shipping weight |
215.5 kg (475 lb) |
660 kg (1500 lb) |
|
|
Shipping dimensions |
0.97 m × 0.58 m × 0.56 m |
0.86 m × 1.22 m × 1.19 m |
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