ABQMR's Gradient Amplifier
The gradient amplifier we have developed is a 3-channel amp and can output pulses up to +-10 amps at +-50 volts.
The prototype is 9"x12.5"x6.75" (LxWxH) and weighs 9 pounds.
The amps are analog, not switching amps; the internal dc power supplies are well-filtered switching supplies.
The input is differential to eliminate 60 Hz interference and is currently adjusted so max output of +-10 amps requires +-10 volts at the differential analog input (XLR cables available on-line or at stereo/ music stores).
If the three channels are run simultaneously, the total supplied current will be no more than 15 amps (of either polarity).
At total currents above 10 amps, the supply will droop after 20 msec.
There is a large internal heatsink with forced air, so gradient coils will overheat before the amplifier does.
The outputs are individually fused (accessible from outside) and the output connections are a screw-termianl block, a touch-safe design.
For safety when setting up new sequences, there is a front-panel halt/run switch.
If any amplifier overheats, there is LED indication (specific to the overheated channel). The monitor port (BNC) is intended for oscilloscope monitoring, if desired.
Available are the voltages on each side of each coil (push-pull drive) and the current through each coil.
While the amplifiers are intended for use in controlled-current mode, each channel can be switched to controlled-voltage, if desired.
Pricing
The grad amp is made to order and its price is dependent on exact customer specifications. Please contact us to discuss your needs and pricing.