Section 3
INSTALLATION
Pole fitting (refer to drawing 11801470).
1. Ensure the poles and pole sleeves are clean and free from debris.
2. Reverse the pole removal sequence above.
Electrical Circuit
Never connect or remove cables from the magnet with the power supply connected. The stored energy
in the magnet can cause arcing resulting in severe injury to personnel or equipment damage.
The magnet has two coils which are connected in series. (Refer to drawing 11801470). The power
supply cables should be connected directly to the dc current terminals marked + and -. Recommended
current cable for the 3470 is stranded copper of 1.5 mm² cross section (16 AWG).
Because the magnet stores a significant amount of energy in its magnetic field, special care should be
taken to insure that the current terminations are secure and cannot work loose in operation. Local
heating at the terminations can cause rapid oxidation leading to a high contact resistance and high
power dissipation at the terminals. If left unattended this can cause enough local heating to damage the
terminals and the coils.
The 3470 Interlocks
The Model 3470 has two thermostats, Elmwood 3450G Part Number 3450G611-1 L50C 89/16. They
are located on the outer coil cooling plate and wired in series. The thermostats are normally closed,
opening when the coil cooling plate temperature exceeds 50°C +/3°C.
Cooling
The Model 3470 can be operated to an average coil temperature of 70°C. Assuming an ambient
laboratory temperature of 20°C and a temperature coefficient of resistivity for copper of 0.0039/°C,
the hot resistance of the coil should not exceed 20% more than the ambient temperature "cold"
resistance. The coil thermostat will open when either coil cooling plate temperature exceeds
approximately 50°C . Clean, cool (16°C - 20°C) water at 1 l/min at 0.3 bar (5 psid) should be used to
cool the 3470 magnet.
The cooling copper tubes are electrically isolated from the coils to avoid electrochemical corrosion.
A 50 micron filter should be placed before the input to the magnet to trap particulates and avoid
unreliable operation of the water flow switch interlock if fitted.
For continuous operation of the magnet it may be appropriate to use a recirculating chiller to reduce
water and drainage costs. The chiller capacity will depend on whether cooling is required for the
magnet alone or magnet and power supply. For the Model 3470 Electromagnet alone a suitable chiller
is the Bay Voltex model: RRS-090.
3-2
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
